Crystal structure of an aminoimidazole riboside kinase from Salmonella enterica: implications for the evolution of the ribokinase superfamily.
The crystal structures of a Salmonella enterica aminoimidazole riboside (AIRs) kinase, its complex with the substrate AIRs, and its complex with AIRs and an ATP analog were determined at 2.6 angstroms, 2.9 angstroms, and 2.7 angstroms, respectively. The product of the Salmonella-specific gene stm4066, AIRs kinase, is a homodimer with one active site per monomer. The core structure, consisting of an eight-stranded beta sheet flanked by eight alpha helices, indicates that AIRs kinase is a member of the ribokinase superfamily. Unlike ribokinase and adenosine kinase in this superfamily, AIRs kinase does not show significant conformational changes upon substrate binding. The active site is covered by a lid formed by residues 16-28 and 86-100. A comparison of the structure of AIRs kinase with other ribokinase superfamily members suggests that the active site lid and conformational changes that occur upon substrate binding may be advanced features in the evolution of the ribokinase superfamily.
Zhang
Yan
Y
Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA.
Dougherty
Michael
M
Downs
Diana M
DM
Ealick
Steven E
SE
D000588:Amines / Q000737:chemistry / Q000378:metabolism; D000595:Amino Acid Sequence; D001665:Binding Sites; D017124:Conserved Sequence / Q000235:genetics; D018360:Crystallography, X-Ray; D019143:Evolution, Molecular; D007093:Imidazoles / Q000737:chemistry / Q000378:metabolism; D008969:Molecular Sequence Data; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D020836:Protein Structure, Quaternary; D019779:Salmonella enterica / Q000201:enzymology*; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity
D000588:Amines; D007093:Imidazoles; D017853:Phosphotransferases (Alcohol Group Acceptor); C022534:ribokinase