Structure-based identification of a novel NTPase from Methanococcus jannaschii.
Almost half of the entire set of predicted genomic products from Methanococcus jannaschii are classified as functionally unknown hypothetical proteins. We present a structure-based identification of the biochemical function of a protein with an as yet unknown function from a M. jannaschii gene, Mj0226. The crystal structure of Mj0226 protein determined at 2.2 A resolution reveals that the protein is a homodimer and each monomer folds into an elongated alpha/beta structure of a new fold family. Comparisons of Mj0226 protein with protein structures in the database, however, indicate that one part of the protein is homologous to some of the nucleotide-binding proteins. Biochemical analysis shows that Mj0226 protein is a novel nucleotide triphosphatase that can efficiently hydrolyze nonstandard nucleotides such as XTP to XMP or ITP to IMP, but not the standard nucleotides, in the presence of Mg2+ or Mn2+ ions.
Hwang
K Y
KY
Structural Biology Center, Korea Institute of Science and Technology, Seoul, South Korea.
Chung
J H
JH
Kim
S H
SH
Han
Y S
YS
Cho
Y
Y
D017766:Acid Anhydride Hydrolases / Q000737:chemistry*; D000595:Amino Acid Sequence; D000604:Amino Acyl-tRNA Synthetases / Q000737:chemistry; D018360:Crystallography, X-Ray; D005418:Flavodoxin / Q000737:chemistry; D019877:Hydroxymethyl and Formyl Transferases / Q000737:chemistry; D007700:Kinetics; D017017:Methanococcus / Q000201:enzymology*; D008954:Models, Biological; D008958:Models, Molecular; D008969:Molecular Sequence Data; D043583:Nucleoside-Triphosphatase; D051026:Phosphoribosylglycinamide Formyltransferase; D010744:Phosphoric Monoester Hydrolases / Q000737:chemistry*; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D013997:Time Factors
D005418:Flavodoxin; D019877:Hydroxymethyl and Formyl Transferases; D051026:Phosphoribosylglycinamide Formyltransferase; C092526:Staphylococcal neutral phosphatase; D010744:Phosphoric Monoester Hydrolases; D017766:Acid Anhydride Hydrolases; D043583:Nucleoside-Triphosphatase; D000604:Amino Acyl-tRNA Synthetases