Crystal structure and substrate specificity of the beta-ketoacyl-acyl carrier protein synthase III (FabH) from Staphylococcus aureus.
beta-Ketoacyl-ACP synthase III (FabH), an essential enzyme for bacterial viability, catalyzes the initiation of fatty acid elongation by condensing malonyl-ACP with acetyl-CoA. We have determined the crystal structure of FabH from Staphylococcus aureus, a Gram-positive human pathogen, to 2 A resolution. Although the overall structure of S. aureus FabH is similar to that of Escherichia coli FabH, the primer binding pocket in S. aureus FabH is significantly larger than that present in E. coli FabH. The structural differences, which agree with kinetic parameters, provide explanation for the observed varying substrate specificity for E. coli and S. aureus FabH. The rank order of activity of S. aureus FabH with various acyl-CoA primers was as follows: isobutyryl- > hexanoyl- > butyryl- > isovaleryl- >> acetyl-CoA. The availability of crystal structure may aid in designing potent, selective inhibitors of S. aureus FabH.
GlaxoSmithKline, King of Prussia, Pennsylvania 19406, USA.
Xiayang
X
Qiu
Anthony E
AE
Choudhry
Cheryl A
CA
Janson
Michael
M
Grooms
Robert A
RA
Daines
John T
JT
Lonsdale
Sanjay S
SS
Khandekar
D015099:3-Oxoacyl-(Acyl-Carrier-Protein) Synthase / Q000737:chemistry* / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000201:enzymology; D007700:Kinetics; D008958:Models, Molecular; D013211:Staphylococcus aureus / Q000201:enzymology*; D013379:Substrate Specificity
D001426:Bacterial Proteins; C077402:3-ketoacyl-acyl carrier protein synthase III; D015099:3-Oxoacyl-(Acyl-Carrier-Protein) Synthase