title: Crystal structure of ST2348, a CBS domain protein, from hyperthermophilic archaeon Sulfolobus tokodaii.
abstract: The crystal structure of a hypothetical protein ST2348 (GI: 47118305) from the hyperthermophilic bacteria Sulfolobus tokodaii has been determined using X-ray crystallography. The protein consists of two CBS (cystathione beta synthase) domains, whose function has been analyzed and reported here. PSI-BLAST shows a conservation of this domain in about 100 proteins in various species. However, none of the close homologs of ST2348 have been functionally characterized so far. Structure and sequence comparison of ST2348 with human AMP-kinase gamma1 subunit and the CBS domain pair of bacterial IMP dehydrogenase is suggestive of its binding to AMP and ATP. A highly conserved residue Asp118, located in a negatively charged patch near the ligand binding cleft, could serve as a site for phosphorylation similar to that found in the chemotatic signal protein CheY and thereby ST2348 can function as a signal transduction molecule.
authors.affiliation: Centre of Advanced Study in Crystallography and Biophysics, University of Madras, Guindy Campus, Chennai 600 025, India.
authors.forename: Preethi
authors.initials: P
authors.lastname: Ragunathan
authors.forename: Thirumananseri
authors.initials: T
authors.lastname: Kumarevel
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Agari
authors.forename: Akeo
authors.initials: A
authors.lastname: Shinkai
authors.forename: Seiki
authors.initials: S
authors.lastname: Kuramitsu
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Yokoyama
authors.forename: Karthe
authors.initials: K
authors.lastname: Ponnuraj
mesh_terms: D019843:Archaeal Proteins / Q000737:chemistry* / Q000378:metabolism; D018360:Crystallography, X-Ray; D003541:Cystathionine beta-Synthase / Q000737:chemistry; D006358:Hot Temperature; D006801:Humans; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D016944:Sulfolobus / Q000201:enzymology*
chemical_list: D019843:Archaeal Proteins; D003541:Cystathionine beta-Synthase