title: Structure of the type III pantothenate kinase from Bacillus anthracis at 2.0 A resolution: implications for coenzyme A-dependent redox biology.
abstract: Coenzyme A (CoASH) is the major low-molecular weight thiol in Staphylococcus aureus and a number of other bacteria; the crystal structure of the S. aureus coenzyme A-disulfide reductase (CoADR), which maintains the reduced intracellular state of CoASH, has recently been reported [Mallett, T.C., Wallen, J.R., Karplus, P.A., Sakai, H., Tsukihara, T., and Claiborne, A. (2006) Biochemistry 45, 11278-89]. In this report we demonstrate that CoASH is the major thiol in Bacillus anthracis; a bioinformatics analysis indicates that three of the four proteins responsible for the conversion of pantothenate (Pan) to CoASH in Escherichia coli are conserved in B. anthracis. In contrast, a novel type III pantothenate kinase (PanK) catalyzes the first committed step in the biosynthetic pathway in B. anthracis; unlike the E. coli type I PanK, this enzyme is not subject to feedback inhibition by CoASH. The crystal structure of B. anthracis PanK (BaPanK), solved using multiwavelength anomalous dispersion data and refined at a resolution of 2.0 A, demonstrates that BaPanK is a new member of the Acetate and Sugar Kinase/Hsc70/Actin (ASKHA) superfamily. The Pan and ATP substrates have been modeled into the active-site cleft; in addition to providing a clear rationale for the absence of CoASH inhibition, analysis of the Pan-binding pocket has led to the development of two new structure-based motifs (the PAN and INTERFACE motifs). Our analyses also suggest that the type III PanK in the spore-forming B. anthracis plays an essential role in the novel thiol/disulfide redox biology of this category A biodefense pathogen.
authors.affiliation: Center for Structural Biology, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157, USA.
authors.forename: Nathan I
authors.initials: NI
authors.lastname: Nicely
authors.forename: Derek
authors.initials: D
authors.lastname: Parsonage
authors.forename: Carleitta
authors.initials: C
authors.lastname: Paige
authors.forename: Gerald L
authors.initials: GL
authors.lastname: Newton
authors.forename: Robert C
authors.initials: RC
authors.lastname: Fahey
authors.forename: Roberta
authors.initials: R
authors.lastname: Leonardi
authors.forename: Suzanne
authors.initials: S
authors.lastname: Jackowski
authors.forename: T Conn
authors.initials: TC
authors.lastname: Mallett
authors.forename: Al
authors.initials: A
authors.lastname: Claiborne
mesh_terms: D000595:Amino Acid Sequence; D001408:Bacillus anthracis / Q000201:enzymology* / Q000378:metabolism; D003065:Coenzyme A / Q000096:biosynthesis / Q000378:metabolism*; D003460:Crystallization; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism; D010084:Oxidation-Reduction; D010205:Pantothenic Acid / Q000378:metabolism; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000737:chemistry* / Q000378:metabolism; D016415:Sequence Alignment
chemical_list: D010205:Pantothenic Acid; D009247:NADH, NADPH Oxidoreductases; C519574:coenzyme A disulfide reductase, Staphylococcus aureus; D017853:Phosphotransferases (Alcohol Group Acceptor); C023088:pantothenate kinase; D003065:Coenzyme A