Displaying publications 121 - 140 of 363 in total

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  1. Fulltext Design and Characterisation of Inhibitory Peptides against Bleg1_2478, an Evolutionary Divergent B3 Metallo-β-lactamase
    Selvaraju G, Leow TC, Salleh AB, Normi YM
    Molecules, 2020 Dec 09;25(24).
    PMID: 33316879 DOI: 10.3390/molecules25245797
    Previously, a hypothetical protein (HP) termed Bleg1_2437 (currently named Bleg1_2478) from Bacillus lehensis G1 was discovered to be an evolutionary divergent B3 subclass metallo-β-lactamase (MBL). Due to the scarcity of clinical inhibitors for B3 MBLs and the divergent nature of Bleg1_2478, this study aimed to design and characterise peptides as inhibitors against Bleg1_2478. Through in silico docking, RSWPWH and SSWWDR peptides with comparable binding energy to ampicillin were obtained. In vitro assay results showed RSWPWH and SSWWDR inhibited the activity of Bleg1_2478 by 50% at concentrations as low as 0.90 µM and 0.50 µM, respectively. At 10 µM of RSWPWH and 20 µM of SSWWDR, the activity of Bleg1_2478 was almost completely inhibited. Isothermal titration calorimetry (ITC) analyses showed slightly improved binding properties of the peptides compared to ampicillin. Docked peptide-protein complexes revealed that RSWPWH bound near the vicinity of the Bleg1_2478 active site while SSWWDR bound at the center of the active site itself. We postulate that the peptides caused the inhibition of Bleg1_2478 by reducing or blocking the accessibility of its active site from ampicillin, thus hampering its catalytic function.
    Matched MeSH terms: Recombinant Proteins/drug effects; Recombinant Proteins/genetics; Recombinant Proteins/chemistry
  2. Fulltext Protein-Protein Interactions: Insight from Molecular Dynamics Simulations and Nanoparticle Tracking Analysis
    Chong WL, Chupradit K, Chin SP, Khoo MM, Khor SM, Tayapiwatana C, et al.
    Molecules, 2021 Sep 20;26(18).
    PMID: 34577167 DOI: 10.3390/molecules26185696
    Protein-protein interaction plays an essential role in almost all cellular processes and biological functions. Coupling molecular dynamics (MD) simulations and nanoparticle tracking analysis (NTA) assay offered a simple, rapid, and direct approach in monitoring the protein-protein binding process and predicting the binding affinity. Our case study of designed ankyrin repeats proteins (DARPins)-AnkGAG1D4 and the single point mutated AnkGAG1D4-Y56A for HIV-1 capsid protein (CA) were investigated. As reported, AnkGAG1D4 bound with CA for inhibitory activity; however, it lost its inhibitory strength when tyrosine at residue 56 AnkGAG1D4, the most key residue was replaced by alanine (AnkGAG1D4-Y56A). Through NTA, the binding of DARPins and CA was measured by monitoring the increment of the hydrodynamic radius of the AnkGAG1D4-gold conjugated nanoparticles (AnkGAG1D4-GNP) and AnkGAG1D4-Y56A-GNP upon interaction with CA in buffer solution. The size of the AnkGAG1D4-GNP increased when it interacted with CA but not AnkGAG1D4-Y56A-GNP. In addition, a much higher binding free energy (∆GB) of AnkGAG1D4-Y56A (-31 kcal/mol) obtained from MD further suggested affinity for CA completely reduced compared to AnkGAG1D4 (-60 kcal/mol). The possible mechanism of the protein-protein binding was explored in detail by decomposing the binding free energy for crucial residues identification and hydrogen bond analysis.
    Matched MeSH terms: Recombinant Proteins/metabolism*; Recombinant Proteins/chemistry
  3. Fulltext Cytoprotective Role of Omentin Against Oxidative Stress-Induced Vascular Endothelial Cells Injury
    Binti Kamaruddin NA, Fong LY, Tan JJ, Abdullah MNH, Singh Cheema M, Bin Yakop F, et al.
    Molecules, 2020 May 29;25(11).
    PMID: 32485974 DOI: 10.3390/molecules25112534
    Endothelial cell injury caused by reactive oxygen species (ROS) plays a critical role in the pathogenesis of cardiovascular diseases. Omentin, an adipocytokine that is abundantly expressed in visceral fat tissue, has been reported to possess anti-inflammatory and antidiabetic properties. However, endothelial protective effects of omentin against oxidative stress remain unclear. This study aimed to evaluate the protective effect of omentin against hydrogen peroxide (H2O2)-induced cell injury in human umbilical vein endothelial cells (HUVECs). Cytotoxicity and cytoprotective effects of omentin were evaluated using 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The apoptotic activity of HUVECs was detected using Annexin-V/PI and Hoechst 33258 staining methods. Antioxidant activity of omentin was evaluated by measuring both reactive oxygen species (ROS) levels and glutathione peroxidase (GPx) activity. No cytotoxicity effect was observed in HUVECs treated with omentin alone at concentrations of 150 to 450 ng/ml. MTT assay showed that omentin significantly prevented the cell death induced by H2O2 (p < 0.001). Hoechst staining and flow cytometry also revealed that omentin markedly prevented H2O2-induced apoptosis. Moreover, omentin not only significantly inhibited ROS production (p < 0.01) but also significantly (p < 0.01) increased GPx activity in HUVECs. In conclusion, our data suggest that omentin may protect HUVECs from injury induced by H2O2.
    Matched MeSH terms: Recombinant Proteins/pharmacology
  4. Fulltext Ion-Pair Interaction and Hydrogen Bonds as Main Features of Protein Thermostability in Mutated T1 Recombinant Lipase Originating from Geobacillus zalihae
    Ishak SNH, Kamarudin NHA, Ali MSM, Leow ATC, Rahman RNZRA
    Molecules, 2020 Jul 28;25(15).
    PMID: 32731607 DOI: 10.3390/molecules25153430
    A comparative structure analysis between space- and an Earth-grown T1 recombinant lipase from Geobacillus zalihae had shown changes in the formation of hydrogen bonds and ion-pair interactions. Using the space-grown T1 lipase validated structure having incorporated said interactions, the recombinant T1 lipase was re-engineered to determine the changes brought by these interactions to the structure and stability of lipase. To understand the effects of mutation on T1 recombinant lipase, five mutants were developed from the structure of space-grown T1 lipase and biochemically characterized. The results demonstrate an increase in melting temperature up to 77.4 °C and 76.0 °C in E226D and D43E, respectively. Moreover, the mutated lipases D43E and E226D had additional hydrogen bonds and ion-pair interactions in their structures due to the improvement of stability, as observed in a longer half-life and an increased melting temperature. The biophysical study revealed differences in β-Sheet percentage between less stable (T118N) and other mutants. As a conclusion, the comparative analysis of the tertiary structure and specific residues associated with ion-pair interactions and hydrogen bonds could be significant in revealing the thermostability of an enzyme with industrial importance.
    Matched MeSH terms: Recombinant Proteins/genetics; Recombinant Proteins/chemistry
  5. In vitro expression of Candida albicans alcohol dehydrogenase genes involved in acetaldehyde metabolism
    Bakri MM, Rich AM, Cannon RD, Holmes AR
    Mol Oral Microbiol, 2015 Feb;30(1):27-38.
    PMID: 24975985 DOI: 10.1111/omi.12064
    Alcohol consumption is a risk factor for oral cancer, possibly via its conversion to acetaldehyde, a known carcinogen. The oral commensal yeast Candida albicans may be one of the agents responsible for this conversion intra-orally. The alcohol dehydrogenase (Adh) family of enzymes are involved in acetaldehyde metabolism in yeast but, for C. albicans it is not known which family member is responsible for the conversion of ethanol to acetaldehyde. In this study we determined the expression of mRNAs from three C. albicans Adh genes (CaADH1, CaADH2 and CaCDH3) for cells grown in different culture media at different growth phases by Northern blot analysis and quantitative reverse transcription polymerase chain reaction. CaADH1 was constitutively expressed under all growth conditions but there was differential expression of CaADH2. CaADH3 expression was not detected. To investigate whether CaAdh1p or CaAdh2p can contribute to alcohol catabolism in C. albicans, each gene from the reference strain C. albicans SC5314 was expressed in Saccharomyces cerevisiae. Cell extracts from an CaAdh1p-expressing S. cerevisiae recombinant, but not an CaAdh2p-expressing recombinant, or an empty vector control strain, possessed ethanol-utilizing Adh activity above endogenous S. cerevisiae activity. Furthermore, expression of C. albicans Adh1p in a recombinant S. cerevisiae strain in which the endogenous ScADH2 gene (known to convert ethanol to acetaldehyde in this yeast) had been deleted, conferred an NAD-dependent ethanol-utilizing, and so acetaldehyde-producing, Adh activity. We conclude that CaAdh1p is the enzyme responsible for ethanol use under in vitro growth conditions, and may contribute to the intra-oral production of acetaldehyde.
    Matched MeSH terms: Recombinant Proteins/metabolism
  6. Effect of recombinant human erythropoietin and doxorubicin in combination on the proliferation of MCF-7 and MDA-MB231 breast cancer cells
    Radwan EM, Abdullah R, Al-Qubaisi MS, El Zowalaty ME, Naadja SE, Alitheen NB, et al.
    Mol Med Rep, 2016 May;13(5):3945-52.
    PMID: 26987078 DOI: 10.3892/mmr.2016.4989
    Patients with cancer often exhibit signs of anemia as the result of the disease. Thus, cancer chemotherapies often include erythropoietin (EPO) in the regime to improve the survival rate of these patients. The aim of the present study was to determine the effect of EPO on doxorubicin-treated breast cancer cells. The cytotoxicity of doxorubicin alone or in combination with EPO against the MCF-7 and MDA-MB‑231 human breast cancer cells were determined using an MTT cell viability assay, neutral red (NR) uptake assay and lactate dehydrogenase (LDH) assay. The estimated half maximal inhibitory concentration values for doxorubicin and the combination of doxorubicin with EPO were between 0.140 and 0.260 µg/ml for all cells treated for 72 h. Treatment with doxorubicin in combination with EPO led to no notable difference in cytotoxicity, compared with treatment with doxorubicin alone. The antiproliferative effect of doxorubicin at a concentration of 1 µg/ml on the MDA‑MB‑231 cells was demonstrated by the decrease in viable cells from 3.6x10(5) at 24 h to 2.1x10(5) at 72 h of treatment. In order to confirm apoptosis in the doxorubicin-treated cells, the activities of caspases-3/7 and ‑9 were determined using a TBE assay. The results indicated that the activities of caspases-3/7 and ‑9 were significantly elevated in the doxorubicin-treated MDA-MB-231 cells by 571 and 645%, respectively, and in the MCF 7 cells by 471 and 345%, respectively, compared with the control cells. EPO did not modify the effect of doxorubicin on these cell lines. The results of the present study suggested that EPO was safe for use in combination with doxorubicin in the treatment of patients with breast cancer and concurrent anemia.
    Matched MeSH terms: Recombinant Proteins/pharmacology
  7. Fulltext Potential use of Pichia pastoris strain SMD1168H expressing DNA topoisomerase I in the screening of potential anti‑breast cancer agents
    Xin J, Wan Mahtar WNA, Siah PC, Miswan N, Khoo BY
    Mol Med Rep, 2019 Jun;19(6):5368-5376.
    PMID: 31059050 DOI: 10.3892/mmr.2019.10201
    Cancer chemotherapy possesses high toxicity, particularly when a higher concentration of drugs is administered to patients. Therefore, searching for more effective compounds to reduce the toxicity of treatments, while still producing similar effects as current chemotherapy regimens, is required. Currently, the search for potential anticancer agents involves a random, inaccurate process with strategic deficits and a lack of specific targets. For this reason, the initial in vitro high‑throughput steps in the screening process should be reviewed for rapid identification of the compounds that may serve as anticancer agents. The present study aimed to investigate the potential use of the Pichia pastoris strain SMD1168H expressing DNA topoisomerase I (SMD1168H‑TOPOI) in a yeast‑based assay for screening potential anticancer agents. The cell density that indicated the growth of the recombinant yeast without treatment was first measured by spectrophotometry. Subsequently, the effects of glutamate (agonist) and camptothecin (antagonist) on the recombinant yeast cell density were investigated using the same approach, and finally, the effect of camptothecin on various cell lines was determined and compared with its effect on recombinant yeast. The current study demonstrated that growth was enhanced in SMD1168H‑TOPOI as compared with that in SMD1168H. Glutamate also enhanced the growth of the SMD1168H; however, the growth effect was not enhanced in SMD1168H‑TOPOI treated with glutamate. By contrast, camptothecin caused only lower cell density and growth throughout the treatment of SMD1168H‑TOPOI. The findings of the current study indicated that SMD1168H‑TOPOI has similar characteristics to MDA‑MB‑231 cells; therefore, it can be used in a yeast‑based assay to screen for more effective compounds that may inhibit the growth of highly metastatic breast cancer cells.
    Matched MeSH terms: Recombinant Proteins/biosynthesis; Recombinant Proteins/genetics
  8. The critical region for viral RNA encapsidation in leader promoter of Nipah virus
    Pong LY, Rabu A, Ibrahim N
    Mol Genet Genomics, 2020 Nov;295(6):1501-1516.
    PMID: 32767127 DOI: 10.1007/s00438-020-01716-3
    Encapsidation by nucleocapsid (N) protein is crucial for viral RNA to serve as a functional template for virus replication. However, the potential region that is vital for RNA encapsidation of Nipah virus (NiV) is still unknown. Thus, this study was aimed to identify these regions using a NiV minireplicon system. A series of broad range internal deletion mutations was generated in the 5' non-translated region (NTR) of the N gene mRNA region of NiV leader promoter via site-directed overlapping PCR-mediated mutagenesis. The mutation effects on synthesis and encapsidation of antigenome RNA, transcription, and RNA binding affinity of N protein were evaluated. The deletions of nucleotides 73-108, 79-108, and 85-108 from NiV leader promoter inhibited the encapsidation of antigenome RNA, while the deletion of nucleotides 103-108 suppressed the synthesis and encapsidation of antigenome RNA, implying that these regions are required for genome replication. Surprisingly, none of the mutations had detrimental effect on viral transcription. Using isothermal titration calorimetry, the binding of NiV N protein to genome or antigenome RNA transcript lacking of nucleotides 73-108 was found to be suppressed. Additionally, in silico analysis on secondary structure of genome RNA further supported the plausible cause of inefficient encapsidation of antigenome RNA by the loss of encapsidation signal in genome template. In conclusion, this study suggests that the nucleotides 73-90 within 5' NTR of the N gene mRNA region in NiV leader promoter contain cis-acting RNA element that is important for efficient encapsidation of antigenome RNA.
    Matched MeSH terms: Recombinant Proteins/genetics
  9. Production of 3-Oxo-2-(2'-pentenyl)-cyclopentane-1-octanoic Acid in the Fungus Aspergillus oryzae: A Step Towards Heterologous Production of Pyrethrins in Fungi
    Mohamed ME, Pahirulzaman KA, Lazarus CM
    Mol Biotechnol, 2016 Mar;58(3):172-8.
    PMID: 26718544 DOI: 10.1007/s12033-015-9911-0
    Pyrethrins are natural insecticides, which accumulate to high concentrations in pyrethrum (Chrysanthemum cinerariaefolium) flowers. Synthetic pyrethroids are more stable, more efficacious and cheaper, but contemporary requirements for safe and environmentally friendly pesticides encourage a return to the use of natural pyrethrins, and this would be favoured by development of an efficient route to their production by microbial fermentation. The biosynthesis of pyrethrins involves ester linkage between an acid moiety (chrysanthemoyl or pyrethroyl, synthesised via the mevalonic acid pathway from glucose), and an alcohol (pyrethrolone). Pyrethrolone is generated from 3-oxo-2-(2'-pentenyl)-cyclopentane-1-octanoic acid, which originates from α-linolenic acid via the jasmonic acid biosynthetic cascade. The first four genes in this cascade, encoding lipoxygenase 2, allene-oxide synthase, allene-oxide cyclase 2 and 12-oxophytodienoic acid reductase 3, were amplified from an Arabidopsis thaliana cDNA library, cloned in a purpose-built fungal multigene expression vector and expressed in Aspergillus oryzae. HPLC-MS analysis of the transgenic fungus homogenate gave good evidence for the presence of 3-oxo-2-(2'-pentenyl)-cyclopentane-1-octanoic acid.
    Matched MeSH terms: Recombinant Proteins/genetics; Recombinant Proteins/metabolism
  10. Unscrambling the effect of C-terminal tail deletion on the stability of a cold-adapted, organic solvent stable lipase from Staphylococcus epidermidis AT2
    Kamarudin NH, Rahman RN, Ali MS, Leow TC, Basri M, Salleh AB
    Mol Biotechnol, 2014 Aug;56(8):747-57.
    PMID: 24771007 DOI: 10.1007/s12033-014-9753-1
    Terminal moieties of most proteins are long known to be disordered and flexible. To unravel the functional role of these regions on the structural stability and biochemical properties of AT2 lipase, four C-terminal end residues, (Ile-Thr-Arg-Lys) which formed a flexible, short tail-like random-coil segment were targeted for mutation. Swapping of the tail-like region had resulted in an improved crystallizability and anti-aggregation property along with a slight shift of the thermostability profile. The lipolytic activity of mutant (M386) retained by 43 % compared to its wild-type with 18 % of the remaining activity at 45 °C. In silico analysis conducted at 25 and 45 °C was found to be in accordance to the experimental findings in which the RMSD values of M386 were more stable throughout the total trajectory in comparison to its wild-type. Terminal moieties were also observed to exhibit large movement and flexibility as denoted by high RMSF values at both dynamics. Variation in organic solvent stability property was detected in M386 where the lipolytic activity was stimulated in the presence of 25 % (v/v) of DMSO, isopropanol, and diethyl ether. This may be worth due to changes in the surface charge residues at the mutation point which probably involve in protein-solvent interaction.
    Matched MeSH terms: Recombinant Proteins/genetics; Recombinant Proteins/metabolism; Recombinant Proteins/chemistry
  11. A New Plant Expression System for Producing Pharmaceutical Proteins
    Abd-Aziz N, Tan BC, Rejab NA, Othman RY, Khalid N
    Mol Biotechnol, 2020 Apr;62(4):240-251.
    PMID: 32108286 DOI: 10.1007/s12033-020-00242-2
    In the past decade, interest in the production of recombinant pharmaceutical proteins in plants has tremendously progressed because plants do not harbor mammalian viruses, are economically competitive, easily scalable, and capable of carrying out complex post-translational modifications required for recombinant pharmaceutical proteins. Mucuna bracteata is an essential perennial cover crop species widely planted as an underground cover in oil palm and rubber plantations. As a legume, they have high biomass, thrive in its habitat, and can fix nitrogen. Thus, M. bracteata is a cost-efficient crop that shows ideal characteristics as a platform for mass production of recombinant protein. In this study, we established a new platform for the transient production of a recombinant protein in M. bracteata via vacuum-assisted agro-infiltration. Five-week-old M. bracteata plants were vacuum infiltrated with Agrobacterium tumefaciens harboring a plasmid that encodes for an anti-toxoplasma immunoglobulin (IgG) under different parameters, including trifoliate leaf positional effects, days to harvest post-infiltration, and the Agrobacterium strain used. Our results showed that vacuum infiltration of M. bracteata plant with A. tumefaciens strain GV3101 produced the highest concentration of heterologous protein in its bottom trifoliate leaf at 2 days post-infiltration. The purified anti-toxoplasma IgG was then analyzed using Western blot and ELISA. It was demonstrated that, while structural heterogeneity existed in the purified anti-toxoplasma IgG from M. bracteata, its transient expression level was two-fold higher than the model platform, Nicotiana benthamiana. This study has laid the foundation towards establishing M. bracteata as a potential platform for the production of recombinant pharmaceutical protein.
    Matched MeSH terms: Recombinant Proteins/metabolism; Recombinant Proteins/pharmacology
  12. The Effects of One Amino Acid Substitutions at the C-Terminal Region of Thermostable L2 Lipase by Computational and Experimental Approach
    Sani HA, Shariff FM, Rahman RNZRA, Leow TC, Salleh AB
    Mol Biotechnol, 2018 Jan;60(1):1-11.
    PMID: 29058211 DOI: 10.1007/s12033-017-0038-3
    The substitutions of the amino acid at the predetermined critical point at the C-terminal of L2 lipase may increase its thermostability and enzymatic activity, or even otherwise speed up the unfolding of the protein structure. The C-terminal of most proteins is often flexible and disordered. However, some protein functions are directly related to flexibility and play significant role in enzyme reaction. The critical point for mutation of L2 lipase structure was predicted at the position 385 of the L2 sequence, and the best three mutants were determined based on I-Mutant2.0 software. The best three mutants were S385E, S385I and S385V. The effects of the substitution of the amino acids at the critical point were analysed with molecular dynamics simulation by using Yet Another Scientific Artificial Reality Application software. The predicted mutant L2 lipases were found to have lower root mean square deviation value as compared to L2 lipase. It was indicated that all the three mutants had higher compactness in the structure, consequently enhanced the stability. Root mean square fluctuation analysis showed that the flexibility of L2 lipase was reduced by mutations. Purified S385E lipase had an optimum temperature of 80 °C in Tris-HCl pH 8. The highest enzymatic activity of purified S385E lipase was obtained at 80 °C temperature in Tris-HCl pH 8, while for L2 lipase it was at 70 °C in Glycine-NaOH pH 9. The thermal stability of S385V lipase was enhanced as compared to other protein since that the melting point (T m) value was at 85.96 °C. S385I lipase was more thermostable compared to recombinant L2 lipase and other mutants at temperature 60 °C within 16 h preincubation.
    Matched MeSH terms: Recombinant Proteins/genetics; Recombinant Proteins/metabolism; Recombinant Proteins/chemistry
  13. Recent Advances in Overexpression of Functional Recombinant Lipases
    Alias FL, Nezhad NG, Normi YM, Ali MSM, Budiman C, Leow TC
    Mol Biotechnol, 2023 Nov;65(11):1737-1749.
    PMID: 36971996 DOI: 10.1007/s12033-023-00725-y
    Heterologous functional expression of the recombinant lipases is typically a bottleneck due to the expression in the insoluble fraction as inclusion bodies (IBs) which are in inactive form. Due to the importance of lipases in various industrial applications, many investigations have been conducted to discover suitable approaches to obtain functional lipase or increase the expressed yield in the soluble fraction. The utilization of the appropriate prokaryotic and eukaryotic expression systems, along with the suitable vectors, promoters, and tags, has been recognized as a practical approach. One of the most powerful strategies to produce bioactive lipases is using the molecular chaperones co-expressed along with the target protein's genes into the expression host to produce the lipase in soluble fraction as a bioactive form. The refolding of expressed lipase from IBs (inactive) is another practical strategy which is usually carried out through chemical and physical methods. Based on recent investigations, the current review simultaneously highlights strategies to express the bioactive lipases and recover the bioactive lipases from the IBs in insoluble form.
    Matched MeSH terms: Recombinant Proteins/chemistry
  14. Gene expression and functional studies of small heat shock protein 37 (MrHSP37) from Macrobrachium rosenbergii challenged with infectious hypodermal and hematopoietic necrosis virus (IHHNV)
    Arockiaraj J, Vanaraja P, Easwvaran S, Singh A, Othman RY, Bhassu S
    Mol Biol Rep, 2012 Jun;39(6):6671-82.
    PMID: 22290288 DOI: 10.1007/s11033-012-1473-7
    In this study, we have reported a full length of small heat shock protein 37 (designated MrHSP37) gene, identified from the transcriptome database of freshwater prawn Macrobrachium rosenbergii. The complete gene sequence of the MrHSP37 is 2,425 base pairs in length, and encodes 338 amino acids. MrHSP37 contains a long heat shock protein family profile in the amino acid sequence between 205 and 288. The mRNA expressions of MrHSP37 in healthy and the infectious hypodermal and hematopoietic necrosis virus (IHHNV) challenged M. rosenbergii were examined using quantitative real time polymerase chain reaction (qRT-PCR). MrHSP37 is highly expressed in hepatopancreas and all the other tissues (walking leg, gills, muscle, stomach, haemocyte, intestine, pleopods, brain and eye stalk) of M. rosenbergii taken for analysis. The expression is strongly up-regulated after IHHNV challenge. To understand its biological activity, the recombinant MrHSP37 gene was constructed and expressed in Escherichia coli BL21 (DE3). The results of ATPase assay showed that the recombinant MrHSP37 protein exhibited apparent ATPase activity which increased with the concentration of the protein. And also the purified recombinant MrHSP37 protein was used for thermal aggregation assay (chaperone activity). It showed that the recombinant MrHSP37 protein is an active chaperone in this assay. Taken together, these results suggest that MrHSP37 is potentially involved in the immune responses against IHHNV challenge in M. rosenbergii.
    Matched MeSH terms: Recombinant Proteins/genetics; Recombinant Proteins/metabolism; Recombinant Proteins/chemistry
  15. Molecular and allergenic characterization of recombinant tropomyosin from mud crab Scylla olivacea
    Azemi NFH, Misnan R, Keong BP, Mokhtar M, Kamaruddin N, Fah WC, et al.
    Mol Biol Rep, 2021 Oct;48(10):6709-6718.
    PMID: 34427887 DOI: 10.1007/s11033-021-06661-x
    BACKGROUND: Tropomyosin is a major allergen in crustaceans, including mud crab species, but its molecular and allergenic properties in Scylla olivacea are not well known. Thus, this study aimed to produce the recombinant tropomyosin protein from S. olivacea and subsequently investigate its IgE reactivity.

    METHODS AND RESULTS: The tropomyosin gene was cloned and expressed in the Escherichia coli system, followed by SDS-PAGE and immunoblotting test to identify the allergenic potential of the recombinant protein. The 855-base pair of tropomyosin gene produced was found to be 99.18% homologous to Scylla serrata. Its 284 amino acids matched the tropomyosin of crustaceans, arachnids, insects, and Klebsiella pneumoniae, ranging from 79.03 to 95.77%. The tropomyosin contained 89.44% alpha-helix folding with a tertiary structure of two-chain alpha-helical coiled-coil structures comprising a homodimer heptad chain. IPTG-induced histidine tagged-recombinant tropomyosin was purified at the size of 42 kDa and confirmed as tropomyosin using anti-tropomyosin monoclonal antibodies. The IgE binding of recombinant tropomyosin protein was reactive in 90.9% (20/22) of the sera from crab-allergic patients.

    CONCLUSIONS: This study has successfully produced an allergenic recombinant tropomyosin from S. olivacea. This recombinant tropomyosin may be used as a specific allergen for the diagnosis of allergy.

    Matched MeSH terms: Recombinant Proteins/genetics*; Recombinant Proteins/immunology*
  16. Fulltext Expression of full-length Plasmodium falciparum P48/45 in P. berghei blood stages: A method to express and evaluate vaccine antigens
    Othman AS, Lin JW, Franke-Fayard BM, Kroeze H, van Pul FJA, Chevalley-Maurel S, et al.
    Mol Biochem Parasitol, 2018 Sep;224:44-49.
    PMID: 30053393 DOI: 10.1016/j.molbiopara.2018.07.009
    The transmission-blocking vaccine candidate Pfs48/45 from the human malaria parasite Plasmodium falciparum is known to be difficult to express in heterologous systems, either as full-length protein or as correctly folded protein fragments that retain conformational epitopes. In this study we express full-length Pfs48/45 in the rodent parasite P. berghei. Pfs48/45 is expressed as a transgene under control of the strong P. berghei schizont-specific msp1 gene promoter (Pfs48/45@PbMSP1). Pfs48/45@PbMSP1 schizont-infected red blood cells produced full-length Pfs48/45 and the structural integrity of Pfs48/45 was confirmed using a panel of conformation-specific monoclonal antibodies that bind to different Pfs48/45 epitopes. Sera from mice immunized with transgenic Pfs48/45@PbMSP1 schizonts showed strong transmission-reducing activity in mosquitoes infected with P. falciparum using standard membrane feeding. These results demonstrate that transgenic rodent malaria parasites expressing human malaria antigens may be used as means to evaluate immunogenicity and functionality of difficult to express malaria vaccine candidate antigens.
    Matched MeSH terms: Recombinant Proteins/biosynthesis; Recombinant Proteins/genetics; Recombinant Proteins/immunology*
  17. Fulltext The Sequence-specific Peptide-binding Activity of the Protein Sulfide Isomerase AGR2 Directs Its Stable Binding to the Oncogenic Receptor EpCAM
    Mohtar MA, Hernychova L, O'Neill JR, Lawrence ML, Murray E, Vojtesek B, et al.
    Mol Cell Proteomics, 2018 04;17(4):737-763.
    PMID: 29339412 DOI: 10.1074/mcp.RA118.000573
    AGR2 is an oncogenic endoplasmic reticulum (ER)-resident protein disulfide isomerase. AGR2 protein has a relatively unique property for a chaperone in that it can bind sequence-specifically to a specific peptide motif (TTIYY). A synthetic TTIYY-containing peptide column was used to affinity-purify AGR2 from crude lysates highlighting peptide selectivity in complex mixtures. Hydrogen-deuterium exchange mass spectrometry localized the dominant region in AGR2 that interacts with the TTIYY peptide to within a structural loop from amino acids 131-135 (VDPSL). A peptide binding site consensus of Tx[IL][YF][YF] was developed for AGR2 by measuring its activity against a mutant peptide library. Screening the human proteome for proteins harboring this motif revealed an enrichment in transmembrane proteins and we focused on validating EpCAM as a potential AGR2-interacting protein. AGR2 and EpCAM proteins formed a dose-dependent protein-protein interaction in vitro Proximity ligation assays demonstrated that endogenous AGR2 and EpCAM protein associate in cells. Introducing a single alanine mutation in EpCAM at Tyr251 attenuated its binding to AGR2 in vitro and in cells. Hydrogen-deuterium exchange mass spectrometry was used to identify a stable binding site for AGR2 on EpCAM, adjacent to the TLIYY motif and surrounding EpCAM's detergent binding site. These data define a dominant site on AGR2 that mediates its specific peptide-binding function. EpCAM forms a model client protein for AGR2 to study how an ER-resident chaperone can dock specifically to a peptide motif and regulate the trafficking a protein destined for the secretory pathway.
    Matched MeSH terms: Recombinant Proteins/metabolism
  18. Fulltext A Host-Vector System for the Expression of a Thermostable Bacterial Lipase in a Locally Isolated Meyerozyma guilliermondii SMB
    Salleh AB, Baharuddin SM, Rahman RNZRA, Leow TC, Basri M, Oslan SN
    Microorganisms, 2020 Nov 06;8(11).
    PMID: 33171893 DOI: 10.3390/microorganisms8111738
    Screening for a new yeast as an alternative host is expected to solve the limitations in the present yeast expression system. A yeast sample which was isolated from the traditional food starter 'ragi' from Malaysia was identified to contain Meyerozyma guilliermondii strain SMB. This yeast-like fungus strain SMB was characterized to assess its suitability as an expression host. Lipase activity was absent in this host (when assayed at 30 °C and 70 °C) and Hygromycin B (50 μg/mL) was found to be its best selection marker. Then, the hyg gene (Hygromycin B) was used to replace the sh ble gene (Zeocin) expression cassette in a Komagataella phaffii expression vector (designated as pFLDhα). A gene encoding the mature thermostable lipase from Bacillus sp. L2 was cloned into pFLDhα, followed by transformation into strain SMB. The optimal expression of L2 lipase was achieved using YPTM (Yeast Extract-Peptone-Tryptic-Methanol) medium after 48 h with 0.5% (v/v) methanol induction, which was 3 times faster than another K. phaffii expression system. In conclusion, a new host-vector system was established as a platform to express L2 lipase under the regulation of PFLD1. It could also be promising to express other recombinant proteins without inducers.
    Matched MeSH terms: Recombinant Proteins
  19. Fulltext Multi-isotype antibody responses against the multimeric Salmonella Typhi recombinant hemolysin E antigen
    Ong EB, Ignatius J, Anthony AA, Aziah I, Ismail A, Lim TS
    Microbiol. Immunol., 2015 Jan;59(1):43-7.
    PMID: 25399538 DOI: 10.1111/1348-0421.12211
    The detection and measurement of different antibody isotypes in the serum provide valuable indicators of the different stages of typhoid infection. Here, the ability of S. Typhi recombinant hemolysin E (HlyE) to detect multi-isotype antibody responses in sera of patients with typhoid and paratyphoid A was investigated using an indirect antibody immunoassay. Nanogram amounts of HlyE were found to be sufficient for detection of IgG and IgA isotypes and, in a study of individuals' sera (n = 100), the immunoassay was able to distinguish between typhoid and non-typhoid sera. The overall sensitivity, specificity and efficiency of the ELISA were 70% (39/56), 100% (44/44) and 83% respectively.
    Matched MeSH terms: Recombinant Proteins/genetics; Recombinant Proteins/immunology
  20. Transcriptome analysis of Burkholderia pseudomallei T6SS identifies Hcp1 as a potential serodiagnostic marker
    Chieng S, Mohamed R, Nathan S
    Microb Pathog, 2015 Feb;79:47-56.
    PMID: 25616255 DOI: 10.1016/j.micpath.2015.01.006
    Burkholderia pseudomallei, the causative agent of melioidosis, is able to survive extreme environments and utilizes various virulence factors for survival and pathogenicity. To compete and survive within these different ecological niches, B. pseudomallei has evolved specialized pathways, including the Type VI secretion systems (T6SSs), that have a role in pathogenesis as well as interbacterial interactions. We examined the expression profile of B. pseudomallei T6SS six gene clusters during infection of U937 macrophage cells. T6SS-5 was robustly transcribed while the other five clusters were not significantly regulated proposing the utility of T6SS-5 as a potential biomarker of exposure to B. pseudomallei. Transcription of T6SS regulators VirAG and BprB was also not significant during infection when compared to bacteria grown in culture. Guided by these findings, three highly expressed T6SS genes, tssJ-4, hcp1 and tssE-5, were expressed as recombinant proteins and screened against melioidosis patient sera by western analysis and ELISA. Only Hcp1 was reactive by both types of analysis. The recombinant Hcp1 protein was further evaluated against a cohort of melioidosis patients (n = 32) and non-melioidosis individuals (n = 20) sera and the data clearly indicates a higher sensitivity (93.7%) and specificity (100%) for Hcp1 compared to bacterial lysate. The detection of anti-Hcp1 antibodies in patients' sera indicating the presence of B. pseudomallei highlights the potential of Hcp1 to be further developed as a serodiagnostic marker for melioidosis.
    Matched MeSH terms: Recombinant Proteins/biosynthesis; Recombinant Proteins/genetics
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