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Updated: Jul 14, 2026

Directed Evolution Method in Saccharomyces cerevisiae: Mutant Library Creation and Screening
Published on: April 1, 2016
Variation in copolymer composition and molecular weight of polyhydroxyalkanoate generated by saturation mutagenesis
Takeharu Tsuge1, Shinko Watanabe, Shun Sato
1Department of Innovative and Engineered Materials, Tokyo Institute of Technology, 4259 Nagatsuta, Yokohama 226-8502, Japan. tsuge.t.aa@m.titech.ac.jp
Abstract:
Amino acid substitutions at two residues downstream from the active-site histidine of polyhydroxyalkanoate (PHA) synthases are effective for changing the composition and the molecular weight of PHA. In this study, saturation mutagenesis at the position Ala505 was applied to PHA synthase (PhaCAc) from Aeromonas caviae to investigate the effects on the composition and the molecular weight of PHA synthesized in Ralstonia eutropha. The copolymer composition and molecular weight of PHA were varied by association with amino acid substitutions. There was a strong relationship between copolymer composition and PHA synthase activity of the cells. This finding will serve as a rationale for producing tailor-made PHAs.
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