scholarly journals Coexpression of Genetically Engineered 3-Ketoacyl-ACP Synthase III (fabH) and Polyhydroxyalkanoate Synthase (phaC) Genes Leads to Short-Chain-Length-Medium-Chain-Length Polyhydroxyalkanoate Copolymer Production from Glucose in Escherichia coli JM109

2004 ◽  
Vol 70 (2) ◽  
pp. 999-1007 ◽  
Author(s):  
Christopher T. Nomura ◽  
Kazunori Taguchi ◽  
Seiichi Taguchi ◽  
Yoshiharu Doi
Keyword(s):  
Escherichia Coli ◽  
Chain Length ◽  
Acyl Carrier Protein ◽  
Short Chain ◽  
Pha Synthase ◽  
Short Chain Length ◽  
E Coli ◽  
Medium Chain ◽  
Medium Chain Length ◽  
Pha Copolymers

ABSTRACT Polyhydroxyalkanoates (PHAs) can be divided into three main types based on the sizes of the monomers incorporated into the polymer. Short-chain-length (SCL) PHAs consist of monomer units of C3 to C5, medium-chain-length (MCL) PHAs consist of monomer units of C6 to C14, and SCL-MCL PHAs consist of monomers ranging in size from C4 to C14. Although previous studies using recombinant Escherichia coli have shown that either SCL or MCL PHA polymers could be produced from glucose, this study presents the first evidence that an SCL-MCL PHA copolymer can be made from glucose in recombinant E. coli. The 3-ketoacyl-acyl carrier protein synthase III gene (fabH) from E. coli was modified by saturation point mutagenesis at the codon encoding amino acid 87 of the FabH protein sequence, and the resulting plasmids were cotransformed with either the pAPAC plasmid, which harbors the Aeromonas caviae PHA synthase gene (phaC), or the pPPAC plasmid, which harbors the Pseudomonas sp. strain 61-3 PHA synthase gene (phaC1), and the abilities of these strains to accumulate PHA from glucose were assessed. It was found that overexpression of several of the mutant fabH genes enabled recombinant E. coli to induce the production of monomers of C4 to C10 and subsequently to produce unusual PHA copolymers containing SCL and MCL units. The results indicate that the composition of PHA copolymers may be controlled by the monomer-supplying enzyme and further reinforce the idea that fatty acid biosynthesis may be used to supply monomers for PHA production.

scholarly journals Identification and Characterization of a New Enoyl Coenzyme A Hydratase Involved in Biosynthesis of Medium-Chain-Length Polyhydroxyalkanoates in Recombinant Escherichia coli

2003 ◽  
Vol 185 (18) ◽  
pp. 5391-5397 ◽  
Author(s):  
Si Jae Park ◽  
Sang Yup Lee
Keyword(s):  
Escherichia Coli ◽  
Fatty Acid ◽  
Chain Length ◽  
Biosynthetic Pathway ◽  
Pha Synthase ◽  
Enzymatic Analysis ◽  
E Coli ◽  
Medium Chain ◽  
Medium Chain Length ◽  
Enoyl Coa Hydratase

ABSTRACT The biosynthetic pathway of medium-chain-length (MCL) polyhydroxyalkanoates (PHAs) from fatty acids has been established in fadB mutant Escherichia coli strain by expressing the MCL-PHA synthase gene. However, the enzymes that are responsible for the generation of (R)-3-hydroxyacyl coenzyme A (R3HA-CoAs), the substrates for PHA synthase, have not been thoroughly elucidated. Escherichia coli MaoC, which is homologous to Pseudomonas aeruginosa (R)-specific enoyl-CoA hydratase (PhaJ1), was identified and found to be important for PHA biosynthesis in a fadB mutant E. coli strain. When the MCL-PHA synthase gene was introduced, the fadB maoC double-mutant E. coli WB108, which is a derivative of E. coli W3110, accumulated 43% less amount of MCL-PHA from fatty acid compared with the fadB mutant E. coli WB101. The PHA biosynthetic capacity could be restored by plasmid-based expression of the maoCEc gene in E. coli WB108. Also, E. coli W3110 possessing fully functional β-oxidation pathway could produce MCL-PHA from fatty acid by the coexpression of the maoCEc gene and the MCL-PHA synthase gene. For the enzymatic analysis, MaoC fused with His6-Tag at its C-terminal was expressed in E. coli and purified. Enzymatic analysis of tagged MaoC showed that MaoC has enoyl-CoA hydratase activity toward crotonyl-CoA. These results suggest that MaoC is a new enoyl-CoA hydratase involved in supplying (R)-3-hydroxyacyl-CoA from the β-oxidation pathway to PHA biosynthetic pathway in the fadB mutant E. coli strain.

scholarly journals Characterization of Site-Specific Mutations in a Short-Chain-Length/Medium-Chain-Length Polyhydroxyalkanoate Synthase:In VivoandIn VitroStudies of Enzymatic Activity and Substrate Specificity

2013 ◽  
Vol 79 (12) ◽  
pp. 3813-3821 ◽  
Author(s):  
Jo-Ann Chuah ◽  
Satoshi Tomizawa ◽  
Miwa Yamada ◽  
Takeharu Tsuge ◽  
Yoshiharu Doi ◽  
...  
Keyword(s):  
Chain Length ◽  
Fold Increase ◽  
Short Chain ◽  
Pha Synthase ◽  
Wild Type ◽  
Short Chain Length ◽  
Medium Chain ◽  
Medium Chain Length

ABSTRACTSaturation point mutagenesis was carried out at position 479 in the polyhydroxyalkanoate (PHA) synthase fromChromobacteriumsp. strain USM2 (PhaCCs) with specificities for short-chain-length (SCL) [(R)-3-hydroxybutyrate (3HB) and (R)-3-hydroxyvalerate (3HV)] and medium-chain-length (MCL) [(R)-3-hydroxyhexanoate (3HHx)] monomers in an effort to enhance the specificity of the enzyme for 3HHx. A maximum 4-fold increase in 3HHx incorporation and a 1.6-fold increase in PHA biosynthesis, more than the wild-type synthase, was achieved using selected mutant synthases. These increases were subsequently correlated with improved synthase activity and increased preference of PhaCCsfor 3HHx monomers. We found that substitutions with uncharged residues were beneficial, as they resulted in enhanced PHA production and/or 3HHx incorporation. Further analysis led to postulations that the size and geometry of the substrate-binding pocket are determinants of PHA accumulation, 3HHx fraction, and chain length specificity.In vitroactivities for polymerization of 3HV and 3HHx monomers were consistent within vivosubstrate specificities. Ultimately, the preference shown by wild-type and mutant synthases for either SCL (C4and C5) or MCL (C6) substrates substantiates the fundamental classification of PHA synthases.

scholarly journals Fructose-Based Production of Short-Chain-Length and Medium-Chain-Length Polyhydroxyalkanoate Copolymer by Arctic Pseudomonas sp. B14-6

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1398
Author(s):  
Tae-Rim Choi ◽  
Ye-Lim Park ◽  
Hun-Suk Song ◽  
Sun Mi Lee ◽  
Sol Lee Park ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Chain Length ◽  
Average Molecular Weight ◽  
Short Chain ◽  
Pha Synthase ◽  
Pseudomonas Sp ◽  
Short Chain Length ◽  
Medium Chain ◽  
Medium Chain Length ◽  
Pha Production

Arctic bacteria employ various mechanisms to survive harsh conditions, one of which is to accumulate carbon and energy inside the cell in the form of polyhydroxyalkanoate (PHA). Whole-genome sequencing of a new Arctic soil bacterium Pseudomonas sp. B14-6 revealed two PHA-production-related gene clusters containing four PHA synthase genes (phaC). Pseudomonas sp. B14-6 produced poly(6% 3-hydroxybutyrate-co-94% 3-hydroxyalkanoate) from various carbon sources, containing short-chain-length PHA (scl-PHA) and medium-chain-length PHA (mcl-PHA) composed of various monomers analyzed by GC-MS, such as 3-hydroxybutyrate, 3-hydroxyhexanoate, 3-hydroxyoctanoate, 3-hydroxydecanoate, 3-hydroxydodecenoic acid, 3-hydroxydodecanoic acid, and 3-hydroxytetradecanoic acid. By optimizing the PHA production media, we achieved 34.6% PHA content using 5% fructose, and 23.7% PHA content using 5% fructose syrup. Differential scanning calorimetry of the scl-co-mcl PHA determined a glass transition temperature (Tg) of 15.3 °C, melting temperature of 112.8 °C, crystallization temperature of 86.8 °C, and 3.82% crystallinity. In addition, gel permeation chromatography revealed a number average molecular weight of 3.6 × 104, weight average molecular weight of 9.1 × 104, and polydispersity index value of 2.5. Overall, the novel Pseudomonas sp. B14-6 produced a polymer with high medium-chain-length content, low Tg, and low crystallinity, indicating its potential use in medical applications.

Synthesis of Short-Chain-Length/Medium-Chain Length Polyhydroxyalkanoate (PHA) Copolymers in Peroxisomes of Transgenic Sugarcane Plants

2011 ◽  
Vol 4 (3-4) ◽  
pp. 170-184 ◽  
Author(s):  
David J. Anderson ◽  
Annathurai Gnanasambandam ◽  
Edwina Mills ◽  
Michael G. O’Shea ◽  
Lars K. Nielsen ◽  
...  
Keyword(s):  
Chain Length ◽  
Short Chain ◽  
Short Chain Length ◽  
Medium Chain ◽  
Medium Chain Length ◽  
Transgenic Sugarcane ◽  
Pha Copolymers

scholarly journals Expression of 3-Ketoacyl-Acyl Carrier Protein Reductase (fabG) Genes Enhances Production of Polyhydroxyalkanoate Copolymer from Glucose in Recombinant Escherichia coli JM109

2005 ◽  
Vol 71 (8) ◽  
pp. 4297-4306 ◽  
Author(s):  
Christopher T. Nomura ◽  
Kazunori Taguchi ◽  
Zhihua Gan ◽  
Kazuhiro Kuwabara ◽  
Tomoyo Tanaka ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Chain Length ◽  
Acyl Carrier Protein ◽  
Carbon Sources ◽  
Pha Synthase ◽  
Carrier Protein ◽  
Substrate Specificities ◽  
E Coli ◽  
Pha Production ◽  
Pha Copolymers

ABSTRACT Polyhydroxyalkanoates (PHAs) are biologically produced polyesters that have potential application as biodegradable plastics. Especially important are the short-chain-length-medium-chain-length (SCL-MCL) PHA copolymers, which have properties ranging from thermoplastic to elastomeric, depending on the ratio of SCL to MCL monomers incorporated into the copolymer. Because of the potential wide range of applications for SCL-MCL PHA copolymers, it is important to develop and characterize metabolic pathways for SCL-MCL PHA production. In previous studies, coexpression of PHA synthase genes and the 3-ketoacyl-acyl carrier protein reductase gene (fabG) in recombinant Escherichia coli has been shown to enhance PHA production from related carbon sources such as fatty acids. In this study, a new fabG gene from Pseudomonas sp. 61-3 was cloned and its gene product characterized. Results indicate that the Pseudomonas sp. 61-3 and E. coli FabG proteins have different substrate specificities in vitro. The current study also presents the first evidence that coexpression of fabG genes from either E. coli or Pseudomonas sp. 61-3 with fabH(F87T) and PHA synthase genes can enhance the production of SCL-MCL PHA copolymers from nonrelated carbon sources. Differences in the substrate specificities of the FabG proteins were reflected in the monomer composition of the polymers produced by recombinant E. coli. SCL-MCL PHA copolymer isolated from a recombinant E. coli strain had improved physical properties compared to the SCL homopolymer poly-3-hydroxybutyrate. This study defines a pathway to produce SCL-MCL PHA copolymer from the fatty acid biosynthesis that may impact on PHA production in recombinant organisms.

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