Biomacromolecules. 2018 Feb 12;19(2):662-671. doi: 10.1021/acs.biomac.7b01768. Epub 2018 Jan 22.

Dynamic Changes of Intracellular Monomer Levels Regulate Block Sequence of Polyhydroxyalkanoates in Engineered Escherichia coli.

Biomacromolecules

Ken'ichiro Matsumoto, Chiaki Hori, Ryunosuke Fujii, Masahiro Takaya, Takashi Ooba, Toshihiko Ooi, Takuya Isono, Toshifumi Satoh, Seiichi Taguchi

PMID: 29323923 DOI: 10.1021/acs.biomac.7b01768

Abstract

Biological polymer synthetic systems, which utilize no template molecules, normally synthesize random copolymers. We report an exception, a synthesis of block polyhydroxyalkanoates (PHAs) in an engineered Escherichia coli. Using an engineered PHA synthase, block copolymers poly[(R)-2-hydroxybutyrate(2HB)-b-(R)-3-hydroxybutyrate(3HB)] were produced in E. coli. The covalent linkage between P(2HB) and P(3HB) segments was verified with solvent fractionation and microphase separation. Notably, the block sequence was generated under the simultaneous consumption of two monomer precursors, indicating the existence of a rapid monomer switching mechanism during polymerization. Based on in vivo metabolic intermediate analysis and the relevant in vitro enzymatic activities, we propose a model in which the rapid intracellular 3HB-CoA fluctuation during polymer synthesis is a major factor in generating block sequences. The dynamic change of intracellular monomer levels is a novel regulatory principle of monomer sequences of biopolymers.

Substances

• Polyhydroxyalkanoates

MeSH terms

• Escherichia coli* / chemistry
• Escherichia coli* / genetics
• Escherichia coli* / metabolism
• Microorganisms, Genetically-Modified* / chemistry
• Microorganisms, Genetically-Modified* / genetics
• Microorganisms, Genetically-Modified* / metabolism
• Polyhydroxyalkanoates* / biosynthesis
• Polyhydroxyalkanoates* / chemistry
• Polyhydroxyalkanoates* / genetics

Publication Types

• Journal Article
• Research Support, Non-U.S. Gov't