In Vitro Analysis of the Chain Termination Reaction in the Synthesis of Poly-(R)-β-hydroxybutyrate by the Class III Synthase from Allochromatium vinosum
- 12 May 2005
- journal article
- research article
- Published by American Chemical Society (ACS) in Biomacromolecules
- Vol. 6 (4), 2113-2119
- https://doi.org/10.1021/bm0501048
Abstract
AllochromatiumVinosum polyhydroxyalkanoate synthase catalyzes formation of poly-(R)-3-hydroxybutyrate (PHB) from (R)-3-hydroxybutyryl-coenzyme A (HB-CoA). (R)-3-Hydroxybutyryl-N-acetylcysteamine (HB- NAC) is an alternative substrate for this synthase in vitro, with a turnover 1% that of HB-CoA. With HB-NAC, the molecular weight (Mw) of PHB produced at substrate-to-enzyme ratios of 1500-15 000 is 75 kDa. 1 H NMR shows that PHB produced has hydroxybutyrate at the alcohol end andN-acetylcysteamine (NAC) at the carboxylate end of the polymer. Exogenous NAC has no effect on the Mw of PHB produced with HB-CoA or HB-NAC in vitro, whereas PHB from a polymerization reaction with both HB-CoA and HB-NAC has intermediate Mw. These results can be accommodated by two models. In the first, NAC liberated at the active site during polymerization acts as a chain transfer agent. In the second, there is a noncovalent polymer intermediate covalently linked to NAC, which can dissociate from the active site.Keywords
This publication has 16 references indexed in Scilit:
- Medical applications of poly-4-hydroxybutyrate: a strong flexible absorbable biomaterialBiochemical Engineering Journal, 2003
- Polyhydroxyalkanoate (PHA) homeostasis: the role of the PHA synthaseNatural Product Reports, 2003
- Structural Basis for the Cyclization of the Lipopeptide Antibiotic Surfactin by the Thioesterase Domain SrfTEStructure, 2002
- Polyhydroxyalkanoate Polymers and Their Production in Transgenic PlantsMetabolic Engineering, 2002
- PhaC and PhaR Are Required for Polyhydroxyalkanoic Acid Synthase Activity in Bacillus megateriumJournal of Bacteriology, 2001
- Synthesis, structure and properties of polyhydroxyalkanoates: biological polyestersProgress in Polymer Science, 2000
- Peter Robert Uldall 1935–1995: A Personal TributeASAIO Journal, 2000
- Polyhydroxybutyrate Synthase: Evidence for Covalent CatalysisJournal of the American Chemical Society, 1996
- A new kinetic model for the accumulation of poly(3‐hydroxybutyrate) in alcaligenes eutrophus, 1. Granule growthMacromolecular Theory and Simulations, 1995
- Diversity of bacterial polyhydroxyalkanoic acidsFEMS Microbiology Letters, 1995