Structure of coenzyme A-disulfide reductase from Staphylococcus aureus at 1.54 A resolution.
Coenzyme A (CoASH) replaces glutathione as the major low molecular weight thiol in Staphylococcus aureus; it is maintained in the reduced state by coenzyme A-disulfide reductase (CoADR), a homodimeric enzyme similar to NADH peroxidase but containing a novel Cys43-SSCoA redox center. The crystal structure of S. aureus CoADR has been solved using multiwavelength anomalous dispersion data and refined at a resolution of 1.54 A. The resulting electron density maps define the Cys43-SSCoA disulfide conformation, with Cys43-S(gamma) located at the flavin si face, 3.2 A from FAD-C4aF, and the CoAS- moiety lying in an extended conformation within a cleft at the dimer interface. A well-ordered chloride ion is positioned adjacent to the Cys43-SSCoA disulfide and receives a hydrogen bond from Tyr361'-OH of the complementary subunit, suggesting a role for Tyr361' as an acid-base catalyst during the reduction of CoAS-disulfide. Tyr419'-OH is located 3.2 A from Tyr361'-OH as well and, based on its conservation in known functional CoADRs, also appears to be important for activity. Identification of residues involved in recognition of the CoAS-disulfide substrate and in formation and stabilization of the Cys43-SSCoA redox center has allowed development of a CoAS-binding motif. Bioinformatics analyses indicate that CoADR enzymes are broadly distributed in both bacterial and archaeal kingdoms, suggesting an even broader significance for the CoASH/CoAS-disulfide redox system in prokaryotic thiol/disulfide homeostasis.
Mallett
T Conn
TC
Center for Structural Biology, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157, USA.
Wallen
Jamie R
JR
Karplus
P Andrew
PA
Sakai
Hiroaki
H
Tsukihara
Tomitake
T
Claiborne
Al
A
D000595:Amino Acid Sequence; D001105:Archaea / Q000201:enzymology; D001665:Binding Sites; D003065:Coenzyme A / Q000737:chemistry*; D018360:Crystallography, X-Ray; D019281:Dimerization; D005182:Flavin-Adenine Dinucleotide / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009247:NADH, NADPH Oxidoreductases / Q000737:chemistry*; D009249:NADP / Q000378:metabolism; D017433:Protein Structure, Secondary; D016415:Sequence Alignment; D012996:Solutions; D013211:Staphylococcus aureus / Q000201:enzymology*
D012996:Solutions; D005182:Flavin-Adenine Dinucleotide; C017145:coenzyme A disulfide; D009249:NADP; D009247:NADH, NADPH Oxidoreductases; C014703:disulfide reductase (NADH); D003065:Coenzyme A