Structure of Staphylococcus aureus1,4-dihydroxy-2-naphthoyl-CoA synthase (MenB) in complex with acetoacetyl-CoA.
Vitamin K(2), or menaquinone, is an essential cofactor for many organisms and the enzymes involved in its biosynthesis are potential antimicrobial drug targets. One of these enzymes, 1,4-dihydroxy-2-naphthoyl-CoA synthase (MenB) from the pathogen Staphylococcus aureus, has been obtained in recombinant form and its quaternary structure has been analyzed in solution. Cubic crystals of the enzyme allowed a low-resolution structure (2.9 A) to be determined. The asymmetric unit consists of two subunits and a crystallographic threefold axis of symmetry generates a hexamer consistent with size-exclusion chromatography. Analytical ultracentrifugation indicates the presence of six states in solution, monomeric through to hexameric, with the dimer noted as being particularly stable. MenB displays the crotonase-family fold with distinct N- and C-terminal domains and a flexible segment of structure around the active site. The smaller C-terminal domain plays an important role in oligomerization and also in substrate binding. The presence of acetoacetyl-CoA in one of the two active sites present in the asymmetric unit indicates how part of the substrate binds and facilitates comparisons with the structure of Mycobacterium tuberculosis MenB.
Ulaganathan
Venkatasubramanian
V
Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Tayside, Scotland.
Agacan
Mark F
MF
Buetow
Lori
L
Tulloch
Lindsay B
LB
Hunter
William N
WN
D000214:Acyl Coenzyme A / Q000737:chemistry*; D001665:Binding Sites; D003001:Cloning, Molecular; D003460:Crystallization; D018360:Crystallography, X-Ray; D007652:Oxo-Acid-Lyases / Q000737:chemistry*; D017510:Protein Folding; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D013211:Staphylococcus aureus / Q000201:enzymology*; D014461:Ultracentrifugation
D000214:Acyl Coenzyme A; C010667:acetoacetyl CoA; D007652:Oxo-Acid-Lyases; C525127:1,4-dihydroxy-2-naphthoyl-CoA synthase, Staphylococcus aureus