title: Crystal structure of the conserved protein TT1542 from Thermus thermophilus HB8.
abstract: The TT1542 protein from Thermus thermophilus HB8 is annotated as a conserved hypothetical protein, and belongs to the DUF158 family in the Pfam database. A BLAST search revealed that homologs of TT1542 are present in a wide range of organisms. The TT1542 homologs in eukaryotes, PIG-L in mammals, and GPI12 in yeast and protozoa, have N-acetylglucosaminylphosphatidylinositol (GlcNAc-PI) de-N-acetylase activity. Although most of the homologs in prokaryotes are hypothetical and have no known function, Rv1082 and Rv1170 from Mycobacterium tuberculosis are enzymes involved in the mycothiol detoxification pathway. Here we report the crystal structure of the TT1542 protein at 2.0 A resolution, which represents the first structure for this superfamily of proteins. The structure of the TT1542 monomer consists of a twisted beta-sheet composed of six parallel beta-strands and one antiparallel beta-strand (with the strand order 3-2-1-4-5-7-6) sandwiched between six alpha-helices. The N-terminal five beta-strands and four alpha-helices form an incomplete Rossmann fold-like structure. The structure shares some similarity to the sugar-processing enzymes with Rossmann fold-like domains, especially those of the GPGTF (glycogen phosphorylase/glycosyl transferase) superfamily, and also to the NAD(P)-binding Rossmann fold domains. TT1542 is a homohexamer in the crystal and in solution, the six monomers forming a cylindrical structure. Putative active sites are suggested by the structure and conserved amino acid residues.
authors.affiliation: RIKEN Genomic Sciences Center, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan.
authors.forename: Noriko
authors.initials: N
authors.lastname: Handa
authors.forename: Takaho
authors.initials: T
authors.lastname: Terada
authors.forename: Yuki
authors.initials: Y
authors.lastname: Kamewari
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Hamana
authors.forename: Jeremy R H
authors.initials: JR
authors.lastname: Tame
authors.forename: Sam-Yong
authors.initials: SY
authors.lastname: Park
authors.forename: Kengo
authors.initials: K
authors.lastname: Kinoshita
authors.forename: Motonori
authors.initials: M
authors.lastname: Ota
authors.forename: Haruki
authors.initials: H
authors.lastname: Nakamura
authors.forename: Seiki
authors.initials: S
authors.lastname: Kuramitsu
authors.forename: Mikako
authors.initials: M
authors.lastname: Shirouzu
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Yokoyama
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry*; D001665:Binding Sites; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D008969:Molecular Sequence Data; D020836:Protein Structure, Quaternary; D055672:Static Electricity; D016963:Thermus thermophilus / Q000737:chemistry*; D014461:Ultracentrifugation
chemical_list: D001426:Bacterial Proteins