Formation of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) by PHA synthase from Ralstonia eutropha.
The acetoacetyl-CoA reductase and the polyhydroxyalkanoate (PHA) synthase from Ralstonia eutropha (formerly Alcaligenes eutrophus) were expressed in Escherichia coli, Klebsiella aerogenes, and PHA-negative mutants of R. eutropha and Pseudomonas putida. While expression in E. coli strains resulted in the accumulation of poly(3-hydroxybutyrate) [PHB], strains of R. eutropha, P. putida and K. aerogenes accumulated poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) [poly(3HB-co-3HHx)] when even chain fatty acids were provided as carbon source, and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [poly(3HB-co-3HV)] when odd chain fatty acids were provided as carbon source. This suggests that fatty acid degradation can be directly accessed employing only the acetoacetyl-CoA reductase and the PHA synthase. This is also the first proof that the PHA synthase from R. eutropha can incorporate 3-hydroxyhexanoate (3HHx) into PHA and has, therefore, a broader substrate specificity than previously described.
Dennis
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D
Department of Biology, James Madison University, Harrisonburg, VA 22807, USA. dennisde@jmu.edu
McCoy
M
M
Stangl
A
A
Valentin
H E
HE
Wu
Z
Z
D020155:3-Hydroxybutyric Acid / Q000378:metabolism; D000217:Acyltransferases / Q000378:metabolism*; D000429:Alcohol Oxidoreductases / Q000378:metabolism; D002208:Caproates / Q000378:metabolism; D002244:Carbon / Q000378:metabolism; D020118:Cupriavidus necator / Q000201:enzymology*; D007711:Klebsiella pneumoniae / Q000235:genetics / Q000254:growth & development; D011995:Recombination, Genetic; D000094122:Polyhydroxybutyrates
D020155:3-Hydroxybutyric Acid; D000217:Acyltransferases; D000429:Alcohol Oxidoreductases; D002208:Caproates; D002244:Carbon; C115940:poly(3-hydroxybutyrate-co-3-hydroxyhexanoate); D000094122:Polyhydroxybutyrates; C023744:acetoacetyl-CoA reductase; C077225:poly(3-hydroxyalkanoic acid) synthase