Displaying publications 1 - 20 of 146 in total

  1. Rizwan K, Rasool N, Rehman R, Mahmood T, Ayub K, Rasheed T, et al.
    Chem Cent J, 2018 Jul 17;12(1):84.
    PMID: 30019193 DOI: 10.1186/s13065-018-0451-0
    A variety of imine derivatives have been synthesized via Suzuki cross coupling of N-(4-bromophenyl)-1-(3-bromothiophen-2-yl)methanimine with various arylboronic acids in moderate to good yields (58-72%). A wide range of electron donating and withdrawing functional groups were well tolerated in reaction conditions. To explore the structural properties, Density functional theory (DFT) investigations on all synthesized molecules (3a-3i) were performed. Conceptual DFT reactivity descriptors and molecular electrostatic potential analyses were performed by using B3LYP/6-31G(d,p) method to explore the reactivity and reacting sites of all derivatives (3a-3i).
    Matched MeSH terms: Catalytic Domain
  2. Teo SH, Yap DKY, Mansir N, Islam A, Taufiq-Yap YH
    Sci Rep, 2019 11 08;9(1):16358.
    PMID: 31705011 DOI: 10.1038/s41598-019-52857-4
    A γ-NA5 catalyst in the form of pellet was first to be reported and was pioneering in gasification to accelerate the production of syngas through biomass (palm empty fruit brunch) conversion. The synthesised γ-NA5 pellet possesses a high surface area of 212.32 m2 g-1, which renders more active sites for hydrocarbon cracking, subsequently leading to high H2 production (0.0716 m3 kg-1). Additionally, the pellet exhibits remarkable reversibility and reusability with 91% H2 production efficiency being retained after five consecutive gasification cycles. Distinctively, the feature of the synthesised γ-NA5 pellet from the conventional powder-like catalyst is that it eases the separation of the used catalyst from the biomass ash, and subsequently facilitates regeneration solely by calcination process. The loading of 20 wt.% optimised amount of catalyst itself has successfully shorten the completion of gasification process up to 135 min, which is highly feasible for a large scale industrial usage after considering the cost of the catalyst, facile preparation method, and catalyst's effectiveness towards gasification.
    Matched MeSH terms: Catalytic Domain
  3. Tai HK, Jusoh SA, Siu SWI
    J Cheminform, 2018 Dec 14;10(1):62.
    PMID: 30552524 DOI: 10.1186/s13321-018-0320-9
    BACKGROUND: Protein-ligand docking programs are routinely used in structure-based drug design to find the optimal binding pose of a ligand in the protein's active site. These programs are also used to identify potential drug candidates by ranking large sets of compounds. As more accurate and efficient docking programs are always desirable, constant efforts focus on developing better docking algorithms or improving the scoring function. Recently, chaotic maps have emerged as a promising approach to improve the search behavior of optimization algorithms in terms of search diversity and convergence speed. However, their effectiveness on docking applications has not been explored. Herein, we integrated five popular chaotic maps-logistic, Singer, sinusoidal, tent, and Zaslavskii maps-into PSOVina[Formula: see text], a recent variant of the popular AutoDock Vina program with enhanced global and local search capabilities, and evaluated their performances in ligand pose prediction and virtual screening using four docking benchmark datasets and two virtual screening datasets.

    RESULTS: Pose prediction experiments indicate that chaos-embedded algorithms outperform AutoDock Vina and PSOVina in ligand pose RMSD, success rate, and run time. In virtual screening experiments, Singer map-embedded PSOVina[Formula: see text] achieved a very significant five- to sixfold speedup with comparable screening performances to AutoDock Vina in terms of area under the receiver operating characteristic curve and enrichment factor. Therefore, our results suggest that chaos-embedded PSOVina methods might be a better option than AutoDock Vina for docking and virtual screening tasks. The success of chaotic maps in protein-ligand docking reveals their potential for improving optimization algorithms in other search problems, such as protein structure prediction and folding. The Singer map-embedded PSOVina[Formula: see text] which is named PSOVina-2.0 and all testing datasets are publicly available on https://cbbio.cis.umac.mo/software/psovina .

    Matched MeSH terms: Catalytic Domain
  4. Mohamed RA, Salleh AB, Leow ATC, Yahaya NM, Abdul Rahman MB
    Mol Biotechnol, 2017 Jul;59(7):284-293.
    PMID: 28580552 DOI: 10.1007/s12033-017-0012-0
    An enzyme with broad substrate specificity would be an asset for industrial application. T1 lipase apparently has the same active site residues as polyhydroxyalkanoates (PHA) depolymerase. Sequences of both enzymes were studied and compared, and a conserved lipase box pentapeptide region around the nucleophilic serine was detected. The alignment of 3-D structures for both enzymes showed their active site residues were well aligned with an RMSD value of 1.981 Å despite their sequence similarity of only 53.8%. Docking of T1 lipase with P(3HB) gave forth high binding energy of 5.4 kcal/mol, with the distance of 4.05 Å between serine hydroxyl (OH) group of TI lipase to the carbonyl carbon of the substrate, similar to the native PhaZ7 Pl . This suggests the possible ability of T1 lipase to bind P(3HB) in its active site. The ability of T1 lipase in degrading amorphous P(3HB) was investigated on 0.2% (w/v) P(3HB) plate. Halo zone was observed around the colony containing the enzyme which confirms that T1 lipase is indeed able to degrade amorphous P(3HB). Results obtained in this study highlight the fact that T1 lipase is a versatile hydrolase enzyme which does not only record triglyceride degradation activity but amorphous P(3HB) degradation activity as well.
    Matched MeSH terms: Catalytic Domain
  5. Rachmawati D, Fahmi MZ, Abdjan MI, Wasito EB, Siswanto I, Mazlan N, et al.
    Molecules, 2022 Dec 15;27(24).
    PMID: 36558064 DOI: 10.3390/molecules27248935
    An anti-biofilm that can inhibit the matrix of biofilm formation is necessary to prevent recurrent and chronic Pseudomonas aeruginosa infection. This study aimed to design compounds with a new mechanism through competitive inhibitory activity against phosphomannomutase/phosphoglucomutase (PMM/PGM), using in vitro assessment and a computational (in silico) approach. The active site of PMM/PGM was assessed through molecular redocking using L-tartaric acid as the native ligand and other small molecules, such as glucaric acid, D-sorbitol, and ascorbic acid. The docking program set the small molecules to the active site, showing a stable complex formation. Analysis of structural similarity, bioavailability, absorption, distribution, metabolism, excretion, and toxicity properties proved the potential application of ligands as an anti-biofilm. In vitro assessment with crystal violet showed that the ligands could reach up to 95.87% inhibition at different concentrations. The nitrocellulose membrane and scanning electron microscopic visualization showed that the untreated P. aeruginosa biofilm was denser than the ligand-treated biofilm.
    Matched MeSH terms: Catalytic Domain
  6. Cheong CSY, Khan SU, Ahmed N, Narayanan K
    J Biomol Struct Dyn, 2023 Jul;41(11):5261-5276.
    PMID: 35694994 DOI: 10.1080/07391102.2022.2084162
    Fabry disease (FD) is caused by a defective α-galactosidase A (α-GAL A) enzyme responsible for breaking down globotriaosylceramide (Gb3). To develop affordable therapeutics, more effort is needed to obtain insights into the underlying mechanism of FD and understanding human α-GAL A structure and function in related animal models. We adopted C. elegans as a model to elucidate the sequence and 3D structure of its GANA-1 enzyme and compared it to human α-GAL A. We constructed GANA-1 3D structure by homology modelling and validated the quality of the predicted GANA-1 structure, followed by computational docking of human ligands. The GANA-1 protein shared sequence similarities up to 42.1% with the human α-GAL A in silico and had dual active sites. GANA-1 homology modelling showed that 11 out of 13 amino acids in the first active site of GANA-1 protein overlapped with the human α-GAL A active site, indicating the prospect for substrate cross-reaction. Computational molecular docking using human ligands like Gb3 (first pocket), 4-nitrophenyl-α-D-galactopyranoside (second pocket), α-galactose (second pocket), and N-acetyl-D-galactosamine (second pocket) showed negative binding energy. This revealed that the ligands were able to bind within both GANA-1 active sites, mimicking the human α-GAL A and α-NAGA enzymes. We identified human compounds with adequate docking scores, predicting robust interactions with the GANA-1 active site. Our data suggested that the C. elegans GANA-1 enzyme may possess structural and functional similarities to human α-GAL A, including an intrinsic capability to metabolize Gb3 deposits.Communicated by Ramaswamy H. Sarma.
    Matched MeSH terms: Catalytic Domain
  7. Rahim F, Javed MT, Ullah H, Wadood A, Taha M, Ashraf M, et al.
    Bioorg Chem, 2015 Oct;62:106-16.
    PMID: 26318401 DOI: 10.1016/j.bioorg.2015.08.002
    A series of thirty (30) thiazole analogs were prepared, characterized by (1)H NMR, (13)C NMR and EI-MS and evaluated for Acetylcholinesterase and butyrylcholinesterase inhibitory potential. All analogs exhibited varied butyrylcholinesterase inhibitory activity with IC50 value ranging between 1.59±0.01 and 389.25±1.75μM when compared with the standard eserine (IC50, 0.85±0.0001μM). Analogs 15, 7, 12, 9, 14, 1, 30 with IC50 values 1.59±0.01, 1.77±0.01, 6.21±0.01, 7.56±0.01, 8.46±0.01, 14.81±0.32 and 16.54±0.21μM respectively showed excellent inhibitory potential. Seven analogs 15, 20, 19, 24, 28, 30 and 25 exhibited good acetylcholinesterase inhibitory potential with IC50 values 21.3±0.50, 35.3±0.64, 36.6±0.70, 44.81±0.81, 46.36±0.84, 48.2±0.06 and 48.72±0.91μM respectively. All other analogs also exhibited well to moderate enzyme inhibition. The binding mode of these compounds was confirmed through molecular docking.
    Matched MeSH terms: Catalytic Domain
  8. Taha M, Ismail NH, Imran S, Mohamad MH, Wadood A, Rahim F, et al.
    Bioorg Chem, 2016 Apr;65:100-9.
    PMID: 26894559 DOI: 10.1016/j.bioorg.2016.02.004
    Benzimidazole analogs 1-27 were synthesized, characterized by EI-MS and (1)HNMR and their α-glucosidase inhibitory activities were found out experimentally. Compound 25, 19, 10 and 20 have best inhibitory activities with IC50 values 5.30±0.10, 16.10±0.10, 25.36±0.14 and 29.75±0.19 respectively against α-glucosidase. Compound 6 and 12 has no inhibitory activity against α-glucosidase enzyme among the series. Further studies showed that the compounds are not showing any cytotoxicity effect. The docking studies of the compounds as well as the experimental activities of the compounds correlated well. From the molecular docking studies, it was observed that the top ranked conformation of all the compounds fit well in the active site of the homology model of α-glucosidase.
    Matched MeSH terms: Catalytic Domain
  9. Sudi IY, Shamsir MS, Jamaluddin H, Wahab RA, Huyop F
    Biotechnology, biotechnological equipment, 2014 Sep 03;28(5):949-957.
    PMID: 26019583
    The D-2-haloacid dehalogenase of D-specific dehalogenase (DehD) from Rhizobium sp. RC1 catalyses the hydrolytic dehalogenation of D-haloalkanoic acids, inverting the substrate-product configuration and thereby forming the corresponding L-hydroxyalkanoic acids. Our investigations were focused on DehD mutants: R134A and Y135A. We examined the possible interactions between these mutants with haloalkanoic acids and characterized the key catalytic residues in the wild-type dehalogenase, to design dehalogenase enzyme(s) with improved potential for dehalogenation of a wider range of substrates. Three natural substrates of wild-type DehD, specifically, monochloroacetate, monobromoacetate and D,L-2,3-dichloropropionate, and eight other non-natural haloalkanoic acids substrates of DehD, namely, L-2-chloropropionate; L-2-bromopropionate; 2,2-dichloropropionate; dichloroacetate; dibromoacetate; trichloroacetate; tribromoacetate; and 3-chloropropionate, were docked into the active site of the DehD mutants R134A and Y135A, which produced altered catalytic functions. The mutants interacted strongly with substrates that wild-type DehD does not interact with or degrade. The interaction was particularly enhanced with 3-chloropropionate, in addition to monobromoacetate, monochloroacetate and D,L-2,3-dichloropropionate. In summary, DehD variants R134A and Y135A demonstrated increased propensity for binding haloalkanoic acid and were non-stereospecific towards halogenated substrates. The improved characteristics in these mutants suggest that their functionality could be further exploited and harnessed in bioremediations and biotechnological applications.
    Matched MeSH terms: Catalytic Domain
  10. Rehman MA, Yusoff I, Alias Y
    J Hazard Mater, 2015 Dec 15;299:316-24.
    PMID: 26143194 DOI: 10.1016/j.jhazmat.2015.06.030
    A series of doped and un-doped magnetic adsorbents CuCexFe2-xO4 (x=0.0-0.5) for fluoride were prepared with the micro-emulsion method. Fluoride adsorption was optimized for solution pH, temperature, contact time, and initial concentration and was monitored via normal phase ion chromatography (IC). The effect of concomitant anions was also explored to perform and simulate competitive fluoride adsorption in real water samples. Optimal adsorption was discovered by a simple quadratic model based on central composite design (CCD) and the response surface method (RSM). The adsorption, electrochemical and magnetic properties were compared between doped and un-doped ferrites. Doped ferrites (x=0.1-0.5) were found to be superior to un-doped ferrites (x=0) regarding the active sites, functional groups and fluoride adsorption. The characterization, optimization and application results of the doped ferrites indicated enhanced fluoride adsorption and easy separation with a simple magnet.
    Matched MeSH terms: Catalytic Domain
  11. Lin XR, Kwon E, Hung C, Huang CW, Oh WD, Lin KA
    J Colloid Interface Sci, 2021 Feb 15;584:749-759.
    PMID: 33176929 DOI: 10.1016/j.jcis.2020.09.104
    As sulfosalicylic acid (SUA) is extensively used as a pharmaceutical product, discharge of SUA into the environment becomes an emerging environmental issue because of its low bio-degradability. Thus, SO4--based advanced oxidation processes have been proposed for degrading SUA because of many advantages of SO4-. As Oxone represents a dominant reagent for producing SO4-, and Co is the most capable metal for activating Oxone to generate SO4-, it is critical to develop an effective but easy-to-use Co-based catalysts for Oxone activation to degrade SUA. Herein, a 3D hierarchical catalyst is specially created by decorating Co3O4 nanocubes (NCs) on macroscale nitrogen-doped carbon form (NCF). This Co3O4-decorated NCF (CONCF) is free-standing, macroscale and even squeezable to exhibit interesting and versatile features. More importantly, CONCF consists of Co3O4 NCs evenly distributed on NCF without aggregation. The NCF not only serves as a support for Co3O4 NCs but also offers additional active sites to synergistically enhance catalytic activities towards Oxone activation. Therefore, CONCF exhibits a higher catalytic activity than the conventional Co3O4 nanoparticles for activating Oxone to fully eliminate SUA in 30 min with a rate constant of 0.142 min-1. CONCF exhibits a much lower Ea value of SUA degradation (35.2 kJ/mol) than reported values, and stable catalytic activities over multi-cyclic degradation of SUA. The mechanism of SUA degradation is also explored, and degradation intermediates of SUA degradation are identified to provide a possible pathway of SUA degradation. These features validate that CONCF is certainly a promising 3D hierarchical catalyst for enhanced Oxone activation to degrade SUA. The findings obtained here are also insightful to develop efficient heterogeneous Oxone-activating catalysts for eliminating emerging contaminants.
    Matched MeSH terms: Catalytic Domain
  12. Chek MF, Kim SY, Mori T, Tan HT, Sudesh K, Hakoshima T
    iScience, 2020 May 22;23(5):101084.
    PMID: 32388399 DOI: 10.1016/j.isci.2020.101084
    Biodegradable polyester polyhydroxyalkanoate (PHA) is a promising bioplastic material for industrial use as a replacement for petroleum-based plastics. PHA synthase PhaC forms an active dimer to polymerize acyl moieties from the substrate acyl-coenzyme A (CoA) into PHA polymers. Here we present the crystal structure of the catalytic domain of PhaC from Chromobacterium sp. USM2, bound to CoA. The structure reveals an asymmetric dimer, in which one protomer adopts an open conformation bound to CoA, whereas the other adopts a closed conformation in a CoA-free form. The open conformation is stabilized by the asymmetric dimerization and enables PhaC to accommodate CoA and also to create the product egress path. The bound CoA molecule has its β-mercaptoethanolamine moiety extended into the active site with the terminal SH group close to active center Cys291, enabling formation of the reaction intermediate by acylation of Cys291.
    Matched MeSH terms: Catalytic Domain
  13. Napi MLM, Sultan SM, Ismail R, How KW, Ahmad MK
    Materials (Basel), 2019 Sep 15;12(18).
    PMID: 31540160 DOI: 10.3390/ma12182985
    Electrochemical biosensors have shown great potential in the medical diagnosis field. The performance of electrochemical biosensors depends on the sensing materials used. ZnO nanostructures play important roles as the active sites where biological events occur, subsequently defining the sensitivity and stability of the device. ZnO nanostructures have been synthesized into four different dimensional formations, which are zero dimensional (nanoparticles and quantum dots), one dimensional (nanorods, nanotubes, nanofibers, and nanowires), two dimensional (nanosheets, nanoflakes, nanodiscs, and nanowalls) and three dimensional (hollow spheres and nanoflowers). The zero-dimensional nanostructures could be utilized for creating more active sites with a larger surface area. Meanwhile, one-dimensional nanostructures provide a direct and stable pathway for rapid electron transport. Two-dimensional nanostructures possess a unique polar surface for enhancing the immobilization process. Finally, three-dimensional nanostructures create extra surface area because of their geometric volume. The sensing performance of each of these morphologies toward the bio-analyte level makes ZnO nanostructures a suitable candidate to be applied as active sites in electrochemical biosensors for medical diagnostic purposes. This review highlights recent advances in various dimensions of ZnO nanostructures towards electrochemical biosensor applications.
    Matched MeSH terms: Catalytic Domain
  14. Mawarnis ER, Ali Umar A, Tomitori M, Balouch A, Nurdin M, Muzakkar MZ, et al.
    ACS Omega, 2018 Sep 30;3(9):11526-11536.
    PMID: 31459253 DOI: 10.1021/acsomega.8b01268
    A combinative effect of two or more individual material properties, such as lattice parameters and chemical properties, has been well-known to generate novel nanomaterials with special crystal growth behavior and physico-chemical performance. This paper reports unusually high catalytic performance of AgPt nanoferns in the hydrogenation reaction of acetone conversion to isopropanol, which is several orders higher compared to the performance shown by pristine Pt nanocatalysts or other metals and metal-metal oxide hybrid catalyst systems. It has been demonstrated that the combinative effect during the bimetallisation of Ag and Pt produced nanostructures with a highly anisotropic morphology, i.e., hierarchical nanofern structures, which provide high-density active sites on the catalyst surface for an efficient catalytic reaction. The extent of the effect of structural growth on the catalytic performance of hierarchical AgPt nanoferns is discussed.
    Matched MeSH terms: Catalytic Domain
  15. Iqbal MZ, Khan A, Numan A, Haider SS, Iqbal J
    Ultrason Sonochem, 2019 Dec;59:104736.
    PMID: 31473424 DOI: 10.1016/j.ultsonch.2019.104736
    An upsurge in sustainable energy demands has ultimately made supercapattery one of the important choice for energy storage, owing to highly advantageous energy density and long life span. In this work, novel strontium based mixed phased nanostructures were synthesized by using probe sonicator with sonication power 500 W at frequency of 20 kHz. The synthesized material was subsequently calcined at different temperature ranging from 200 to 800 °C. Structural and morphological analysis of the synthesized materials reveals the formation of mixed particle and rod like nanostructures with multiple crystal phases of strontium oxides and carbonates. Crystallinity, grain size and morphology of grown nanomaterials significantly improved with the increase of calcination temperature due to sufficient particle growth and low agglomeration. The electrochemical performance analysis confirms the redox activeness of the Sr-based electrode materials. Material calcined at 600 °C show high specific capacitance of 350 F g-1 and specific capacity of 175 C g-1 at current density of 0.3 A g-1 due to less particle agglomeration, good charge transfer and more contribution of electrochemical active sites for redox reactions. In addition, the developed supercapattery of Sr-based nanomaterials//activated carbon demonstrated high performance with maximum energy density of 21.8 Wh kg-1 and an excellent power density of 2400 W kg-1 for the lower and higher current densities. Furthermore, the supercapattery retain 87% of its capacity after continuous 3000 charge/discharge cycles. The device characteristics were further investigated by analyzing the capacitive and diffusion controlled contributions. The versatile strategy of developing mixed phased nanomaterials pave the way to synthesize other transition metal based nanomaterials with superior electrochemical performance for hybrid energy storage devices.
    Matched MeSH terms: Catalytic Domain
  16. Abuelizz HA, Anouar EH, Ahmad R, Azman NIIN, Marzouk M, Al-Salahi R
    PLoS One, 2019;14(8):e0220379.
    PMID: 31412050 DOI: 10.1371/journal.pone.0220379
    Previously, we synthesized triazoloquinazolines 1-14 and characterized their structure. In this study, we aimed to evaluate the in vitro activity of the targets 1-14 as α-glucosidase inhibitors using α-glucosidase enzyme from Saccharomyces cerevisiae type 1. Among the tested compounds, triazoloquinazolines 14, 8, 4, 5, and 3 showed the highest inhibitory activity (IC50 = 12.70 ± 1.87, 28.54 ± 1.22, 45.65 ± 4.28, 72.28 ± 4.67, and 83.87 ± 5.12 μM, respectively) in relation to that of acarbose (IC50 = 143.54 ± 2.08 μM) as a reference drug. Triazoloquinazolines were identified herein as a new class of potent α-glucosidase inhibitors. Molecular docking results envisaged the plausible binding interaction between the target triazoloquinazolines and α-glucosidase enzyme and indicated considerable interaction with the active site residues.
    Matched MeSH terms: Catalytic Domain
  17. Taha M, Rahim F, Ali M, Khan MN, Alqahtani MA, Bamarouf YA, et al.
    Molecules, 2019 Apr 18;24(8).
    PMID: 31003424 DOI: 10.3390/molecules24081528
    Chromen-4-one substituted oxadiazole analogs 1-19 have been synthesized, characterized and evaluated for β-glucuronidase inhibition. All analogs exhibited a variable degree of β-glucuronidase inhibitory activity with IC50 values ranging in between 0.8 ± 0.1-42.3 ± 0.8 μM when compared with the standard d-saccharic acid 1,4 lactone (IC50 = 48.1 ± 1.2 μM). Structure activity relationship has been established for all compounds. Molecular docking studies were performed to predict the binding interaction of the compounds with the active site of enzyme.
    Matched MeSH terms: Catalytic Domain
  18. Hasdianty Abdullah, Mohd Fadzli Ahmad, Farah Aula Mohd Fauzi, Nor Suhaila Yaacob, Abdul Latif Ibrahim
    Protein function depends greatly on its structure. Based on this principle, it is vital to study the
    protein structure in order to understand its function. This study attempts to build the predicted
    model of lipase gene in Rhodococcus sp. NAM81 using homology modelling method. The
    predicted structure was then used to investigate the function of protein through several
    bioinformatic tools. The DNA sequence of lipase gene was obtained from the Rhodococcus sp.
    NAM81 genome scaffold. Blastx analysis showed 100% identity to the target enzyme andthe
    appropriate template for homology modelling was determined using Blastp analysis. The 3D
    protein structure was built using two homology modelling software, EsyPred3D and Swiss
    Model Server. Both structures built obtained LGScore of greater than 4, which means they are
    extremely good models according to ProQ validation criteria. Both structures also satisfied the
    Ramachandran plot structure validation analysis. The predicted structures were 100% matched
    with each other when superimposed with DaliLite pairwise. This shows that both structure
    validation servers agreed on the same model. Structure analysis using ProFunc had found seven
    motifs and active sites that indicate similar function of this protein with other known proteins.
    Thus, this study has successfully produced a good 3D protein structure for the target enzyme.
    Matched MeSH terms: Catalytic Domain
  19. Mazlan SNHS, Ali MSM, Rahman RNZRA, Sabri S, Jonet MA, Leow TC
    Int J Biol Macromol, 2018 Nov;119:1188-1194.
    PMID: 30102982 DOI: 10.1016/j.ijbiomac.2018.08.022
    GDSL esterase J15 (EstJ15) is a member of Family II of lipolytic enzyme. The enzyme was further classified in subgroup SGNH hydrolase due to the presence of highly conserve motif, Ser-Gly-Asn-His in four conserved blocks I, II, III, and V, respectively. X-ray quality crystal of EstJ15 was obtained from optimized formulation containing 0.10 M ammonium sulphate, 0.15 M sodium cacodylate trihydrate pH 6.5, and 20% PEG 8000. The crystal structure of EstJ15 was solved at 1.38 Å with one molecule per asymmetric unit. The structure exhibits α/β hydrolase fold and shared low amino acid sequence identity of 23% with the passenger domain of the autotransporter EstA of Pseudomonas aeruginosa. The active site is located at the centre of the structure, formed a narrow tunnel that hinder long substrates to be catalysed which was proven by the protein-ligand docking analysis. This study facilitates the understanding of high substrate specificity of EstJ15 and provide insights on its catalytic mechanism.
    Matched MeSH terms: Catalytic Domain
  20. Ker DS, Chan KG, Othman R, Hassan M, Ng CL
    Phytochemistry, 2020 May;173:112286.
    PMID: 32059132 DOI: 10.1016/j.phytochem.2020.112286
    The chemical formation of terpenes in nature is carried out by terpene synthases as the main biocatalysts to guide the carbocation intermediate to form structurally diverse compounds including acyclic, mono- and multiple cyclic products. Despite intensive study of the enzyme active site, the mechanism of specific terpene biosynthesis remains unclear. Here we demonstrate that a single mutation of the amino acid L454G or L454A in the active site of Persicaria minor β-sesquiphellandrene synthase leads to a more promiscuous enzyme that is capable of producing additional hydroxylated sesquiterpenes such as sesquicineole, sesquisabinene hydrate and α-bisabolol. Furthermore, the same L454 residue mutation (L454G or L454A) in the active site also improves the protein homogeneity compared to the wild type protein. Taken together, our results demonstrate that residue Leucine 454 in the active site of β-sesquiphellandrene synthase is important for sesquiterpene product diversity as well as the protein homogeneity in solution.
    Matched MeSH terms: Catalytic Domain
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