Biosynthesis of poly-beta-hydroxybutyrate (PHB) is controlled by CydR (Fnr) in the obligate aerobe Azotobacter vinelandii.
CydR is an Fnr-like protein in the obligatory aerobic nitrogen-fixing bacterium Azotobacter vinelandii. The cydR mutant overproduces the cytochrome bd terminal oxidase. Using two-dimensional polyacrylamide gel electrophoresis, we showed that beta-ketothiolase and acetoacetyl-CoA reductase were also overexpressed in the cydR mutant. Fumarase C and a coenzyme A transferase, possibly succinyl-SCoA transferase, were decreased in this mutant. Enzyme assays confirmed the elevated beta-ketothiolase and acetoacetyl-CoA reductase activities in this mutant. The cydR mutant accumulated poly-beta-hydroxybutyrate throughout the exponential growth phase, unlike the wild-type strain that only accumulated poly-beta-hydroxybutyrate during stationary phase. The results demonstrate that CydR controls poly-beta-hydroxybutyrate synthesis in A. vinelandii.
Wu
G
G
The Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, The University of Sheffield, UK.
Moir
A J
AJ
Sawers
G
G
Hill
S
S
Poole
R K
RK
D016948:Azotobacter vinelandii / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D006885:Hydroxybutyrates / Q000378:metabolism*; D011091:Polyesters / Q000378:metabolism*; D012097:Repressor Proteins / Q000378:metabolism*; D000094122:Polyhydroxybutyrates
D001426:Bacterial Proteins; D006885:Hydroxybutyrates; D011091:Polyesters; D012097:Repressor Proteins; C107798:CydR protein, Azotobacter vinelandii; C003182:poly-beta-hydroxybutyrate; D000094122:Polyhydroxybutyrates