Exploring Class I polyhydroxyalkanoate synthases with broad substrate specificity for polymerization of structurally diverse monomer units.

Autor: Sivashankari RM; Department of Materials Science and Engineering, Tokyo Institute of Technology, Yokohama, Japan., Mierzati M; Department of Materials Science and Engineering, Tokyo Institute of Technology, Yokohama, Japan., Miyahara Y; Department of Materials Science and Engineering, Tokyo Institute of Technology, Yokohama, Japan., Mizuno S; Department of Materials Science and Engineering, Tokyo Institute of Technology, Yokohama, Japan., Nomura CT; Department of Biological Sciences, College of Science, University of Idaho, Moscow, ID, United States., Taguchi S; Graduate School of Science, Technology and Innovation, Kobe University, Kobe, Japan., Abe H; Bioplastic Research Team, RIKEN Center for Sustainable Resource Science, Wako, Japan., Tsuge T; Department of Materials Science and Engineering, Tokyo Institute of Technology, Yokohama, Japan.
Jazyk: angličtina
Zdroj: Frontiers in bioengineering and biotechnology [Front Bioeng Biotechnol] 2023 Feb 21; Vol. 11, pp. 1114946. Date of Electronic Publication: 2023 Feb 21 (Print Publication: 2023).
DOI: 10.3389/fbioe.2023.1114946
Abstrakt: Polyhydroxyalkanoate (PHA) synthases (PhaCs) are key enzymes in PHA polymerization. PhaCs with broad substrate specificity are attractive for synthesizing structurally diverse PHAs. In the PHA family, 3-hydroxybutyrate (3HB)-based copolymers are industrially produced using Class I PhaCs and can be used as practical biodegradable thermoplastics. However, Class I PhaCs with broad substrate specificities are scarce, prompting our search for novel PhaCs. In this study, four new PhaCs from the bacteria Ferrimonas marina , Plesiomonas shigelloides , Shewanella pealeana , and Vibrio metschnikovii were selected via a homology search against the GenBank database, using the amino acid sequence of Aeromonas caviae PHA synthase (PhaC Ac ), a Class I enzyme with a wide range of substrate specificities, as a template. The four PhaCs were characterized in terms of their polymerization ability and substrate specificity, using Escherichia coli as a host for PHA production. All the new PhaCs were able to synthesize P(3HB) in E. coli with a high molecular weight, surpassing PhaC Ac . The substrate specificity of PhaCs was evaluated by synthesizing 3HB-based copolymers with 3-hydroxyhexanoate, 3-hydroxy-4-methylvalerate, 3-hydroxy-2-methylbutyrate, and 3-hydroxypivalate monomers. Interestingly, PhaC from P. shigelloides (PhaC Ps ) exhibited relatively broad substrate specificity. PhaC Ps was further engineered through site-directed mutagenesis, and the variant resulted in an enzyme with improved polymerization ability and substrate specificity.
Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
(Copyright © 2023 Sivashankari, Mierzati, Miyahara, Mizuno, Nomura, Taguchi, Abe and Tsuge.)
Databáze: MEDLINE
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