Molecular aspects of beta-ketoacyl synthase (KAS) catalysis.
Crystal structure data for Escherichia coli beta-ketoacyl synthase (KAS) I with C(10) and C(12) fatty acid substrates bound in conjunction with results from mutagenizing residues in the active site leads to a model for catalysis. Differences from and similarities to the other Claisen enzymes carrying out decarboxylations reveal two catalytic mechanisms, one for KAS I and KAS II, the other for KAS III and chalcone synthase. A comparison of the structures of KAS I and KAS II does not reveal the basis of chain-length specificity. The structures of the Arabidopsis thaliana KAS family are compared.
von Wettstein-Knowles
P
P
Genetics Department, Molecular Biology Institute, Copenhagen University, Oester Farimagsgade 2A, DK-1353 Copenhagen K, Denmark. knowles@biobase.dk
Olsen
J
J
Arnvig Mcguire
K
K
Larsen
S
S
D015099:3-Oxoacyl-(Acyl-Carrier-Protein) Synthase / Q000737:chemistry* / Q000378:metabolism*; D017360:Arabidopsis / Q000201:enzymology; D001665:Binding Sites; D002384:Catalysis; D019281:Dimerization; D004926:Escherichia coli / Q000201:enzymology; D007527:Isoenzymes / Q000737:chemistry* / Q000378:metabolism*; D008958:Models, Molecular; D020675:Peroxisomes / Q000201:enzymology; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D012441:Saccharomyces cerevisiae / Q000201:enzymology; D013379:Substrate Specificity
D007527:Isoenzymes; C078182:beta-ketoacyl-acyl carrier protein synthase I; D015099:3-Oxoacyl-(Acyl-Carrier-Protein) Synthase