title: Structure of E. coli ketopantoate hydroxymethyl transferase complexed with ketopantoate and Mg2+, solved by locating 160 selenomethionine sites.
abstract: We report the crystal structure of E. coli ketopantoate hydroxymethyltransferase (KPHMT) at 1.9 A resolution, in complex with its product, ketopantoate. KPHMT catalyzes the first step in the biosynthesis of pantothenate (vitamin B(5)), the precursor of coenzyme A and the acyl carrier protein cofactor. The structure of the decameric enzyme was solved by multiwavelength anomalous dispersion to locate 160 selenomethionine sites and phase 560 kDa of protein, making it the largest structure solved by this approach. KPHMT adopts the (betaalpha)(8) barrel fold and is a member of the phosphoenolpyruvate/pyruvate superfamily. The active site contains a ketopantoate bidentately coordinated to Mg(2+). Similar binding is likely for the substrate, alpha-ketoisovalerate, orienting the C3 for deprotonation.
authors.affiliation: Department of Biochemistry, 80 Tennis Court Road, Cambridge CB2 1GA, United Kingdom.
authors.forename: Frank
authors.initials: F
authors.lastname: von Delft
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Inoue
authors.forename: S Adrian
authors.initials: SA
authors.lastname: Saldanha
authors.forename: Harald H
authors.initials: HH
authors.lastname: Ottenhof
authors.forename: Florian
authors.initials: F
authors.lastname: Schmitzberger
authors.forename: Louise M
authors.initials: LM
authors.lastname: Birch
authors.forename: Venugopal
authors.initials: V
authors.lastname: Dhanaraj
authors.forename: Michael
authors.initials: M
authors.lastname: Witty
authors.forename: Alison G
authors.initials: AG
authors.lastname: Smith
authors.forename: Tom L
authors.initials: TL
authors.lastname: Blundell
authors.forename: Chris
authors.initials: C
authors.lastname: Abell
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D018360:Crystallography, X-Ray; D019281:Dimerization; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D015870:Gene Expression; D019877:Hydroxymethyl and Formyl Transferases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008274:Magnesium / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D015394:Molecular Structure; D008970:Molecular Weight; D010205:Pantothenic Acid / Q000096:biosynthesis; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D012645:Selenomethionine / Q000737:chemistry*; D017386:Sequence Homology, Amino Acid; D013059:Spectrum Analysis, Raman; D055672:Static Electricity; D013379:Substrate Specificity
chemical_list: D011994:Recombinant Proteins; D010205:Pantothenic Acid; D012645:Selenomethionine; D019877:Hydroxymethyl and Formyl Transferases; C021477:3-methyl-2-oxobutanoate hydroxymethyltransferase; D008274:Magnesium