Biosynthesis of Random-Homo Block Copolymer Poly[Glycolate-ran-3-Hydroxybutyrate (3HB)]-b-Poly(3HB) Using Sequence-Regulating Chimeric Polyhydroxyalkanoate Synthase in Escherichia coli.

ABSTRACT: Glycolate (GL)-containing polyhydroxyalkanoate (PHA) was synthesized in Escherichia coli expressing the engineered chimeric PHA synthase PhaC _AR and coenzyme A transferase. The cells produced poly[GL-co-3-hydroxybutyrate (3HB)] with the supplementation of GL and 3HB, thus demonstrating that PhaC _AR is the first known class I PHA synthase that is capable of incorporating GL units. The triad sequence analysis using ¹H nuclear magnetic resonance indicated that the obtained polymer was composed of two distinct regions, a P(GL-ran-3HB) random segment and P(3HB) homopolymer segment. The random segment was estimated to contain a 71 mol% GL molar ratio, which was much greater than the value (15 mol%) previously achieved by using PhaC1 _{P s} STQK. Differential scanning calorimetry analysis of the polymer films supported the presence of random copolymer and homopolymer phases. The solvent fractionation of the polymer indicated the presence of a covalent linkage between these segments. Therefore, it was concluded that PhaC _AR synthesized a novel random-homo block copolymer, P(GL-ran-3HB)-b-P(3HB).

SUBMITTER: Arai S 

PROVIDER: S-EPMC7752996 | biostudies-literature | 2020

REPOSITORIES: biostudies-literature