Displaying publications 1 - 20 of 44 in total

  1. Shafie NA, Lau NS, Ramachandran H, Amirul AA
    Genome Announc, 2017 Jan 19;5(3).
    PMID: 28104662 DOI: 10.1128/genomeA.01498-16
    Cupriavidus sp. USMAA1020, USMAA2-4, and USMAHM13 are capable of producing polyhydroxyalkanoate (PHA). This biopolymer is an alternative solution to synthetic plastics, whereby polyhydroxyalkanoate synthase is the key enzyme involved in PHA biosynthesis. Here, we report the complete genomes of three Cupriavidus sp. strains: USMAA1020, USMAA2-4, and USMAHM13.
    Matched MeSH terms: Acyltransferases
  2. Anis SN, Iqbal NM, Kumar S, Al-Ashraf A
    Bioengineered, 2013 Mar-Apr;4(2):115-8.
    PMID: 23018620 DOI: 10.4161/bioe.22350
    A simple procedure for recovering biodegradable polymer from bacterial cells has been developed using economical and environmentally friendly solvent or chemicals. Recombinant bacterium, Cupriavidus necator harboring pBBR1MCS-C2 plasmid polyhydroxyalkanoate (PHA) synthase gene was used for the production of copolymer P(3HB-co-3HHx) from crude palm kernel oil (CPKO). NaOH was chosen in this study as it could give high purity and recovery yield. Increase of NaOH concentration had resulted in an increase of the PHA purity, but the recovery yield had decreased. The greater improvement of PHA purity and recovery were achieved by incubating the freeze-dried cells (10-30 g/L) in NaOH (0.1 M) for 1-3 h at 30°C and polishing using 20% (v/v) of ethanol. The treatment caused negligible degradation of the molecular weight of PHA recovered from the bacterial cells. The present review also highlights other extraction methods to provide greater insights into economical and sustainable recovery of PHA from bacterial cells.
    Matched MeSH terms: Acyltransferases/genetics; Acyltransferases/metabolism
  3. Chek MF, Kim SY, Mori T, Arsad H, Samian MR, Sudesh K, et al.
    Sci Rep, 2017 07 13;7(1):5312.
    PMID: 28706283 DOI: 10.1038/s41598-017-05509-4
    Polyhydroxyalkanoate (PHA) is a promising candidate for use as an alternative bioplastic to replace petroleum-based plastics. Our understanding of PHA synthase PhaC is poor due to the paucity of available three-dimensional structural information. Here we present a high-resolution crystal structure of the catalytic domain of PhaC from Chromobacterium sp. USM2, PhaC Cs -CAT. The structure shows that PhaC Cs -CAT forms an α/β hydrolase fold comprising α/β core and CAP subdomains. The active site containing Cys291, Asp447 and His477 is located at the bottom of the cavity, which is filled with water molecules and is covered by the partly disordered CAP subdomain. We designated our structure as the closed form, which is distinct from the recently reported catalytic domain from Cupriavidus necator (PhaC Cn -CAT). Structural comparison showed PhaC Cn -CAT adopting a partially open form maintaining a narrow substrate access channel to the active site, but no product egress. PhaC Cs -CAT forms a face-to-face dimer mediated by the CAP subdomains. This arrangement of the dimer is also distinct from that of the PhaC Cn -CAT dimer. These findings suggest that the CAP subdomain should undergo a conformational change during catalytic activity that involves rearrangement of the dimer to facilitate substrate entry and product formation and egress from the active site.
    Matched MeSH terms: Acyltransferases/metabolism; Acyltransferases/chemistry*
  4. Teh AH, Chiam NC, Furusawa G, Sudesh K
    Int J Biol Macromol, 2018 Nov;119:438-445.
    PMID: 30048726 DOI: 10.1016/j.ijbiomac.2018.07.147
    Polyhydroxyalkanoate (PHA) synthase, PhaC, is a key enzyme in the biosynthesis of PHA, a type of bioplastics with huge potential to replace petroleum-based plastics. While two structures have been determined, the exact mechanism remains unclear partly due to the absence of a tunnel for product passage. A model of the class I PhaC from Aquitalea sp. USM4, characterised with Km of 394 μM and kcat of 476 s-1 on 3-(R)-hydroxybutyryl-CoA, revealed a three-branched channel at the dimeric interface. Two of them are opened to the solvent and are expected to serve as the putative routes for substrate entrance and product exit, while the third is elongated in the class II PhaC1 model from Pseudomonas aeruginosa, indicating a role in accommodating the hydroxyalkanoate (HA) moiety of a HA-CoA substrate. Docking of the two tetrahedral intermediates, formed during the transfer of the growing PHA chain from the catalytic Cys to a new molecule of substrate and back to Cys, suggests a common elongation mechanism requiring the HA moiety of the ligand to rotate ~180°. Substrate specificity is determined in part by a bulky Phe/Tyr/Trp residue in the third branch in class I, which is conserved as Ala in class II to create room for longer substrates.
    Matched MeSH terms: Acyltransferases/metabolism*; Acyltransferases/chemistry*
  5. Rahman RN, Zakaria II, Salleh AB, Basri M
    Int J Mol Sci, 2012;13(8):9673-91.
    PMID: 22949824 DOI: 10.3390/ijms13089673
    PpCHS is a member of the type III polyketide synthase family and catalyses the synthesis of the flavonoid precursor naringenin chalcone from p-coumaroyl-CoA. Recent research reports the production of pyrone derivatives using either hexanoyl-CoA or butyryl-CoA as starter molecule. The Cys-His-Asn catalytic triad found in other plant chalcone synthase predicted polypeptides is conserved in PpCHS. Site directed mutagenesis involving these amino acids residing in the active-site cavity revealed that the cavity volume of the active-site plays a significant role in the selection of starter molecules as well as product formation. Substitutions of Cys 170 with Arg and Ser amino acids decreased the ability of the PpCHS to utilize hexanoyl-CoA as a starter molecule, which directly effected the production of pyrone derivatives (products). These substitutions are believed to have a restricted number of elongations of the growing polypeptide chain due to the smaller cavity volume of the mutant's active site.
    Matched MeSH terms: Acyltransferases/genetics; Acyltransferases/metabolism*; Acyltransferases/chemistry
  6. Kosterin OE, Kompier T
    Zootaxa, 2018 Jun 06;4429(2):281-294.
    PMID: 30313268 DOI: 10.11646/zootaxa.4429.2.4
    Amphicnemis valentini sp. nov. is described from the Ream Peninsula of Cambodia (holotype: Cambodia, Preah Sihanouk Province, Ream Peninsula, 10.52258 N 103.69556 E, RMNH) and Phú Quốc Island, Kien Giang Province of Vietnam, both in the Cardamom ecoregion. It is similar to A. gracilis Krüger, 1898, which occurs in Peninsular Malaysia and Sumatra, but differs from it by a long process on the male prothorax.
    Matched MeSH terms: Acyltransferases
  7. Foong CP, Lau NS, Deguchi S, Toyofuku T, Taylor TD, Sudesh K, et al.
    BMC Microbiol, 2014;14:318.
    PMID: 25539583 DOI: 10.1186/s12866-014-0318-z
    Special features of the Japanese ocean include its ranges of latitude and depth. This study is the first to examine the diversity of Class I and II PHA synthases (PhaC) in DNA samples from pelagic seawater taken from the Japan Trench and Nankai Trough from a range of depths from 24 m to 5373 m. PhaC is the key enzyme in microorganisms that determines the types of monomer units that are polymerized into polyhydroxyalkanoate (PHA) and thus affects the physicochemical properties of this thermoplastic polymer. Complete putative PhaC sequences were determined via genome walking, and the activities of newly discovered PhaCs were evaluated in a heterologous host.
    Matched MeSH terms: Acyltransferases/genetics*; Acyltransferases/isolation & purification*; Acyltransferases/metabolism
  8. Bhubalan K, Chuah JA, Shozui F, Brigham CJ, Taguchi S, Sinskey AJ, et al.
    Appl Environ Microbiol, 2011 May;77(9):2926-33.
    PMID: 21398494 DOI: 10.1128/AEM.01997-10
    The synthesis of bacterial polyhydroxyalkanoates (PHA) is very much dependent on the expression and activity of a key enzyme, PHA synthase (PhaC). Many efforts are being pursued to enhance the activity and broaden the substrate specificity of PhaC. Here, we report the identification of a highly active wild-type PhaC belonging to the recently isolated Chromobacterium sp. USM2 (PhaC(Cs)). PhaC(Cs) showed the ability to utilize 3-hydroxybutyrate (3HB), 3-hydroxyvalerate (3HV), and 3-hydroxyhexanoate (3HHx) monomers in PHA biosynthesis. An in vitro assay of recombinant PhaC(Cs) expressed in Escherichia coli showed that its polymerization of 3-hydroxybutyryl-coenzyme A activity was nearly 8-fold higher (2,462 ± 80 U/g) than that of the synthase from the model strain C. necator (307 ± 24 U/g). Specific activity using a Strep2-tagged, purified PhaC(Cs) was 238 ± 98 U/mg, almost 5-fold higher than findings of previous studies using purified PhaC from C. necator. Efficient poly(3-hydroxybutyrate) [P(3HB)] accumulation in Escherichia coli expressing PhaC(Cs) of up to 76 ± 2 weight percent was observed within 24 h of cultivation. To date, this is the highest activity reported for a purified PHA synthase. PhaC(Cs) is a naturally occurring, highly active PHA synthase with superior polymerizing ability.
    Matched MeSH terms: Acyltransferases/genetics*; Acyltransferases/metabolism*; Acyltransferases/chemistry
  9. Zain NA, Ng LM, Foong CP, Tai YT, Nanthini J, Sudesh K
    Curr Microbiol, 2020 Mar;77(3):500-508.
    PMID: 31893298 DOI: 10.1007/s00284-019-01852-z
    A novel polyhydroxyalkanoate (PHA)-producing bacterium, Jeongeupia sp. USM3 (JCM 19920) was isolated from the limestone soil at Gua Tempurung, Perak, Malaysia. This is the first report on the complete genome sequence for the genus Jeongeupia. This genome consists of a circular chromosome with a size of 3,788,814 bp and contains 3557 genes. Two PHA synthase (phaC) genes encoding for the key enzyme in the polymerization of PHA monomers and other PHA-associated genes were identified from the genome. Phylogenetic analysis of the PhaC protein sequences has revealed that both PhaC1 and PhaC2 of Jeongeupia sp. USM3 are categorized as Class I PHA synthases with 56% similarity to each other. Both of the PHA synthase genes of this isolate were cloned and heterologously expressed in a PHA mutant strain Cupriavidus necator PHB-4. The ability of the transformants to accumulate PHA showed that both PhaC1 and PhaC2 were functional.
    Matched MeSH terms: Acyltransferases/genetics; Acyltransferases/metabolism*
  10. Syafiq IM, Huong KH, Shantini K, Vigneswari S, Aziz NA, Amirul AA, et al.
    Enzyme Microb Technol, 2017 Mar;98:1-8.
    PMID: 28110659 DOI: 10.1016/j.enzmictec.2016.11.011
    Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) [P(3HB-co-4HB)] copolymer is noted for its high biocompatibility, which makes it an excellent candidate for biopharmaceutical applications. The wild-type Cupriavidus sp. USMAA1020 strain is able to synthesize P(3HB-co-4HB) copolymers with different 4HB monomer compositions (up to 70mol%) in shaken flask cultures. Combinations of 4HB carbon precursors consisting of 1,6-hexanediol and γ-butyrolactone were applied for the production of P(3HB-co-4HB) with different 4HB molar fraction. A sharp increase in 4HB monomer composition was attained by introducing additional copies of PHA synthase gene (phaC), responsible for P(3HB-co-4HB) polymerization. The phaC of Cupriavidus sp. USMAA1020 and Cupriavidus sp. USMAA2-4 were cloned and heterologously introduced into host, wild-type Cupriavidus sp. USMAA1020. The gene dosage treatment resulted in the accumulation of 93mol% 4HB by the transformant strains when grown in similar conditions as the wild-type USMAA1020. The PHA synthase activities for both transformants were almost two-fold higher than the wild-type. The ability of the transformants to produce copolymers with high 4HB monomer composition was also tested in large scale production system using 5L and 30L bioreactors with a constant oxygen mass transfer rate. The 4HB monomer composition could be maintained at a range of 83-89mol%. The mechanical and thermal properties of copolymers improved with increasing 4HB monomer composition. The copolymers produced could be tailored for specific biopharmaceutical applications based on their properties.
    Matched MeSH terms: Acyltransferases/genetics; Acyltransferases/metabolism
  11. Lau NS, Tsuge T, Sudesh K
    Appl Microbiol Biotechnol, 2011 Mar;89(5):1599-609.
    PMID: 21279348 DOI: 10.1007/s00253-011-3097-6
    Burkholderia sp. synthase has been shown to polymerize 3-hydroxybutyrate (3HB), 3-hydroxyvalerate, and 3-hydroxy-4-pentenoic acid monomers. This study was carried out to evaluate the ability of Burkholderia sp. USM (JCM 15050) and its transformant harboring the polyhydroxyalkanoate (PHA) synthase gene of Aeromonas caviae to incorporate the newly reported 3-hydroxy-4-methylvalerate (3H4MV) monomer. Various culture parameters such as concentrations of nutrient rich medium, fructose and 4-methylvaleric acid as well as harvesting time were manipulated to produce P(3HB-co-3H4MV) with different 3H4MV compositions. The structural properties of PHA containing 3H4MV monomer were investigated by using nuclear magnetic resonance and Fourier transform infrared spectroscopy (FTIR). The relative intensities of the bands at 1,183 and 1,228 cm⁻¹ in the FTIR spectra enabled the rapid detection and differentiation of P(3HB-co-3H4MV) from other types of PHA. In addition, the presence of 3H4MV units in the copolymer was found to considerably lower the melting temperature and enthalpy of fusion values compared with poly(3-hydroxybutyrate) (P(3HB)). The copolymer exhibited higher thermo-degradation temperature but similar molecular weight and polydispersity compared with P(3HB).
    Matched MeSH terms: Acyltransferases/genetics; Acyltransferases/metabolism*
  12. Norhafini H, Huong KH, Amirul AA
    Int J Biol Macromol, 2019 Mar 15;125:1024-1032.
    PMID: 30557643 DOI: 10.1016/j.ijbiomac.2018.12.121
    P(3HB-co-4HB) with a high 4HB monomer composition was previously successfully produced using the transformant Cupriavidus malaysiensis USMAA1020 containing an additional copy of the PHA synthase gene. In this study, high PHA density fed-batch cultivation strategies were developed for such 4HB-rich P(3HB-co-4HB). The pulse, constant and mixed feeding strategies resulted in high PHA accumulation, with a PHA content of 74-92 wt% and 4HB monomer composition of 92-99 mol%. The pulse-feed of carbon and nitrogen resulted in higher PHA concentration (30.7 g/L) than carbon alone (22.3 g/L), suggesting that a trace amount of nitrogen is essential to support cell density for PHA accumulation. Constant feeding was found to be a more feasible strategy than mixed feeding, since the latter caused a drastic fluctuation in the C/N ratio, as evidenced by higher biomass formation indicating more carbon flux towards the competitive TCA pathway. A two-times carbon and nitrogen pulse feeding was the most optimal strategy achieving 92 wt% accommodation of the total biomass, with the highest PHA concentration (46 g/L) and yield (Yp/x) of 11.5 g/g. The strategy has kept the C/N at optimal ratio during the active PHA-producing phase. This is the first report of the production of high PHA density for 4HB-rich P(3HB-co-4HB).
    Matched MeSH terms: Acyltransferases/genetics; Acyltransferases/metabolism*
  13. Yee LN, Chuah JA, Chong ML, Phang LY, Raha AR, Sudesh K, et al.
    Microbiol Res, 2012 Oct 12;167(9):550-7.
    PMID: 22281521 DOI: 10.1016/j.micres.2011.12.006
    In this study, PHA biosynthesis operon of Comamonas sp. EB172, an acid-tolerant strain, consisting of three genes encoding acetyl-CoA acetyltransferase (phaA(Co) gene, 1182 bp), acetoacetyl-CoA reductase (phaB(Co) gene, 738 bp) and PHA synthase, class I (phaC(Co) gene, 1694 bp) were identified. Sequence analysis of the phaA(Co), phaB(Co) and phaC(Co) genes revealed that they shared more than 85%, 89% and 69% identity, respectively, with orthologues from Delftia acidovorans SPH-1 and Acidovorax ebreus TPSY. The PHA biosynthesis genes (phaC(Co) and phaAB(Co)) were successfully cloned in a heterologous host, Escherichia coli JM109. E. coli JM109 transformants harbouring pGEM'-phaC(Co)AB(Re) and pGEM'-phaC(Re)AB(Co) were shown to be functionally active synthesising 33 wt.% and 17 wt.% of poly(3-hydroxybutyrate) [P(3HB)]. E. coli JM109 transformant harbouring the three genes from the acid-tolerant Comamonas sp. EB172 (phaCAB(Co)) under the control of native promoter from Cupriavidus necator, in vivo polymerised P(3HB) when fed with glucose and volatile mixed organic acids (acetic acid:propionic acid:n-butyric acid) in ration of 3:1:1, respectively. The E. coli JM109 transformant harbouring phaCAB(Co) could accumulate P(3HB) at 2g/L of propionic acid. P(3HB) contents of 40.9% and 43.6% were achieved by using 1% of glucose and mixed organic acids, respectively.
    Matched MeSH terms: Acyltransferases/genetics*; Acyltransferases/metabolism; Acyltransferases/chemistry
  14. Zakaria II, Rahman RN, Salleh AB, Basri M
    Appl Biochem Biotechnol, 2011 Sep;165(2):737-47.
    PMID: 21633820 DOI: 10.1007/s12010-011-9292-1
    Flavonoids are secondary metabolites synthesized by plants shown to exhibit health benefits such as anti-inflammatory, antioxidant, and anti-tumor effects. Thus, due to the importance of this compound, several enzymes involved in the flavonoid pathway have been cloned and characterized in Escherichia coli. However, the formation of inclusion bodies has become a major disadvantage of this approach. As an alternative, chalcone synthase from Physcomitrella patens was secreted into the medium using a bacteriocin release protein expression vector. Secretion of P. patens chalcone synthase into the culture media was achieved by co-expression with a psW1 plasmid encoding bacteriocin release protein in E. coli Tuner (DE3) plysS. The optimized conditions, which include the incubation of cells for 20 h with 40 ng/ml mitomycin C at OD(600) induction time of 0.5 was found to be the best condition for chalcone synthase secretion.
    Matched MeSH terms: Acyltransferases/genetics; Acyltransferases/metabolism*; Acyltransferases/chemistry
  15. Tai YT, Foong CP, Najimudin N, Sudesh K
    J Biosci Bioeng, 2016 Apr;121(4):355-64.
    PMID: 26467694 DOI: 10.1016/j.jbiosc.2015.08.008
    PHA synthase (PhaC) is the key enzyme in the production of biodegradable plastics known as polyhydroxyalkanoate (PHA). Nevertheless, most of these enzymes are isolated from cultivable bacteria using traditional isolation method. Most of the microorganisms found in nature could not be successfully cultivated due to the lack of knowledge on their growth conditions. In this study, a culture-independent approach was applied. The presence of phaC genes in limestone soil was screened using primers targeting the class I and II PHA synthases. Based on the partial gene sequences, a total of 19 gene clusters have been identified and 7 clones were selected for full length amplification through genome walking. The complete phaC gene sequence of one of the clones (SC8) was obtained and it revealed 81% nucleotide identity to the PHA synthase gene of Chromobacterium violaceum ATCC 12472. This gene obtained from uncultured bacterium was successfully cloned and expressed in a Cupriavidus necator PHB(-)4 PHA-negative mutant resulting in the accumulation of significant amount of PHA. The PHA synthase activity of this transformant was 64 ± 12 U/g proteins. This paper presents a pioneering study on the discovery of phaC in a limestone area using metagenomic approach. Through this study, a new functional phaC was discovered from uncultured bacterium. Phylogenetic classification for all the phaCs isolated from this study has revealed that limestone hill harbors a great diversity of PhaCs with activities that have not yet been investigated.
    Matched MeSH terms: Acyltransferases
  16. Ng LM, Sudesh K
    J Biosci Bioeng, 2016 Nov;122(5):550-557.
    PMID: 27132174 DOI: 10.1016/j.jbiosc.2016.03.024
    Aquitalea sp. USM4 (JCM 19919) was isolated from a freshwater sample at Lata Iskandar Waterfall in Perak, Malaysia. It is a rod-shaped, gram-negative bacterium with high sequence identity (99%) to Aquitalea magnusonii based on 16S rRNA gene analysis. Aquitalea sp. USM4 also possessed a PHA synthase gene (phaC), which had amino acid sequence identity of 77-78% to the PHA synthase of Chromobacterium violaceum ATCC12472 and Pseudogulbenkiania sp. NH8B. PHA biosynthesis results showed that wild-type Aquitalea sp. USM4 was able to accumulate up to 1.5 g/L of poly(3-hydroxybutyrate), [P(3HB)]. The heterologous expression of the PHA synthase gene of Aquitalea sp. USM4 (phaCAq) in Cupriavidus necator PHB(-)4 had resulted in PHA accumulation up to 3.2 g/L of P(3HB). It was further confirmed by (1)H nuclear magnetic resonance (NMR) analysis that Aquitalea sp. USM4 and C. necator PHB(-)4 transformant were able to produce PHA containing 3-hydroxyvalerate (3HV), 4-hydroxybutyrate (4HB) and 3-hydroxy-4-methylvalerate (3H4MV) monomers from suitable precursor substrates. Interestingly, relatively high PHA synthase activity of 863 U/g and 1402 U/g were determined in wild-type Aquitalea sp. USM4 and C. necator PHB(-)4 transformant respectively. This is the first report on the member of genus Aquitalea as a new PHA producer as well as in vitro and in vivo characterization of a novel PHA synthase from Aquitalea sp. USM4.
    Matched MeSH terms: Acyltransferases/genetics*; Acyltransferases/isolation & purification; Acyltransferases/metabolism*
  17. 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: Acyltransferases
  18. Lau NS, Sudesh K
    AMB Express, 2012;2(1):41.
    PMID: 22877240 DOI: 10.1186/2191-0855-2-41
    The nutrition-versatility of Burkholderia sp. strain USM (JCM 15050) has initiated the studies on the use of this bacterium for polyhydroxyalkanoate (PHA) production. To date, the Burkholderia sp. has been reported to synthesize 3-hydroxybutyrate, 3-hydroxyvalerate and 3-hydroxy-4-methylvalerate monomers. In this study, the PHA biosynthetic genes of this strain were successfully cloned and characterized. The PHA biosynthetic cluster of this strain consisted of a PHA synthase (phaC), β-ketothiolase (phaA), acetoacetyl-CoA reductase (phaB) and PHA synthesis regulator (phaR). The translated products of these genes revealed identities to corresponding proteins of Burkholderia vietnamiensis (99-100 %) and Cupriavidus necator H16 (63-89%). Heterologous expression of phaCBs conferred PHA synthesis to the PHA-negative Cupriavidus necator PHB¯4, confirming that phaCBs encoded functionally active protein. PHA synthase activity measurements revealed that the crude extracts of C. necator PHB¯4 transformant showed higher synthase activity (243 U/g) compared to that of wild-types Burkholderia sp. (151 U/g) and C. necator H16 (180 U/g). Interestingly, the transformant C. necator PHB¯4 harbouring Burkholderia sp. PHA synthase gene accumulated poly(3-hydroxybutyrate-co-4-hydroxybutyrate) with 4-hydroxybutyrate monomer as high as up to 87 mol% from sodium 4-hydroxybutyrate. The wild type Burkholderia sp. did not have the ability to produce this copolymer.
    Matched MeSH terms: Acyltransferases
  19. Vigneswari S, Chai JM, Kamarudin KH, Amirul AA, Focarete ML, Ramakrishna S
    Front Bioeng Biotechnol, 2020;8:567693.
    PMID: 33195129 DOI: 10.3389/fbioe.2020.567693
    Biomaterial scaffolds play crucial role to promote cell proliferation and foster the regeneration of new tissues. The progress in material science has paved the way for the generation of ingenious biomaterials. However, these biomaterials require further optimization to be effectively used in existing clinical treatments. It is crucial to develop biomaterials which mimics structure that can be actively involved in delivering signals to cells for the formation of the regenerated tissue. In this research we nanoengineered a functional scaffold to support the proliferation of myoblast cells. Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) [P(3HB-co-4HB)] copolymer is chosen as scaffold material owing to its desirable mechanical and physical properties combined with good biocompatibility, thus eliciting appropriate host tissue responses. In this study P(3HB-co-4HB) copolymer was biosynthesized using Cupriavidus malaysiensis USMAA1020 transformant harboring additional PHA synthase gene, and the viability of a novel P(3HB-co-4HB) electrospun nanofiber scaffold, surface functionalized with RGD peptides, was explored. In order to immobilize RGD peptides molecules onto the P(3HB-co-4HB) nanofibers surface, an aminolysis reaction was performed. The nanoengineered scaffolds were characterized using SEM, organic elemental analysis (CHN analysis), FTIR, surface wettability and their in vitro degradation behavior was evaluated. The cell culture study using H9c2 myoblast cells was conducted to assess the in vitro cellular response of the engineered scaffold. Our results demonstrated that nano-P(3HB-co-4HB)-RGD scaffold possessed an average fiber diameter distribution between 200 and 300 nm, closely biomimicking, from a morphological point of view, the structural ECM components, thus acting as potential ECM analogs. This study indicates that the surface conjugation of biomimetic RGD peptide to the nano-P(3HB-co-4HB) fibers increased the surface wettability (15 ± 2°) and enhanced H9c2 myoblast cells attachment and proliferation. In summary, the study reveals that nano-P(3HB-co-4HB)-RGD scaffold can be considered a promising candidate to be further explored as cardiac construct for building cardiac construct.
    Matched MeSH terms: Acyltransferases
  20. Ling SC, Tsuge T, Sudesh K
    J Appl Microbiol, 2011 Sep;111(3):559-71.
    PMID: 21689225 DOI: 10.1111/j.1365-2672.2011.05084.x
    Polyhydroxyalkanoate (PHA) with enhanced physicochemical properties will be ideal for a wide range of practical applications. The incorporation of 3-hydroxy-4-methylvalerate (3H4MV) into the polymer backbone is known to improve the overall properties of the resulting polymer. However, the most suitable micro-organism and PHA synthase that can synthesize this monomer efficiently still remain unknown at present. Therefore, we evaluated the abilities of a locally isolated Chromobacterium sp. USM2 to produce PHA containing 3H4MV.
    Matched MeSH terms: Acyltransferases/metabolism
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