title: Crystal structure of a hypothetical protein, TTHA0829 from Thermus thermophilus HB8, composed of cystathionine-β-synthase (CBS) and aspartate-kinase chorismate-mutase tyrA (ACT) domains.
abstract: TTHA0829 from Thermus thermophilus HB8 has a molecular mass of 22,754 Da and is composed of 210 amino acid residues. The expression of TTHA0829 is remarkably elevated in the latter half of logarithmic growth phase. TTHA0829 can form either a tetrameric or dimeric structure, and main-chain folding provides an N-terminal cystathionine-β-synthase (CBS) domain and a C-terminal aspartate-kinase chorismate-mutase tyrA (ACT) domain. Both CBS and ACT are regulatory domains to which a small ligand molecule can bind. The CBS domain is found in proteins from organisms belonging to all kingdoms and is observed frequently as two or four tandem copies. This domain is considered as a small intracellular module with a regulatory function and is typically found adjacent to the active (or functional) site of several enzymes and integral membrane proteins. The ACT domain comprises four β-strands and two α-helices in a βαββαβ motif typical of intracellular small molecule binding domains that help control metabolism, solute transport and signal transduction. We discuss the possible role of TTHA0829 based on its structure and expression pattern. The results imply that TTHA0829 acts as a cell-stress sensor or a metabolite acceptor.
authors.affiliation: Graduate School of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori-cho, Ako-gun, Hyogo, 678-1297, Japan. makoto-n.str@tmd.ac.jp.|Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushima-naka, Kita-ku, Okayama, 700-8530, Japan. makoto-n.str@tmd.ac.jp.
authors.forename: Makoto
authors.initials: M
authors.lastname: Nakabayashi
authors.affiliation: Graduate School of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori-cho, Ako-gun, Hyogo, 678-1297, Japan. shibach@sci.u-hyogo.ac.jp.|RIKEN SPring-8 Center, Harima Institute, 1-1-1 Koto, Sayo-cho, Sayo-Gun, Hyogo, 679-5148, Japan. shibach@sci.u-hyogo.ac.jp.
authors.forename: Naoki
authors.initials: N
authors.lastname: Shibata
authors.affiliation: RIKEN SPring-8 Center, Harima Institute, 1-1-1 Koto, Sayo-cho, Sayo-Gun, Hyogo, 679-5148, Japan.
authors.forename: Emi
authors.initials: E
authors.lastname: Ishido-Nakai
authors.affiliation: RIKEN SPring-8 Center, Harima Institute, 1-1-1 Koto, Sayo-cho, Sayo-Gun, Hyogo, 679-5148, Japan.
authors.forename: Mayumi
authors.initials: M
authors.lastname: Kanagawa
authors.affiliation: Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka, 560-0043, Japan.
authors.forename: Yota
authors.initials: Y
authors.lastname: Iio
authors.affiliation: Graduate School of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori-cho, Ako-gun, Hyogo, 678-1297, Japan.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Komori
authors.affiliation: Graduate School of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori-cho, Ako-gun, Hyogo, 678-1297, Japan.
authors.forename: Yasufumi
authors.initials: Y
authors.lastname: Ueda
authors.affiliation: Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka, 560-0043, Japan.
authors.forename: Noriko
authors.initials: N
authors.lastname: Nakagawa
authors.affiliation: Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka, 560-0043, Japan.
authors.forename: Seiki
authors.initials: S
authors.lastname: Kuramitsu
authors.affiliation: Graduate School of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori-cho, Ako-gun, Hyogo, 678-1297, Japan.|RIKEN SPring-8 Center, Harima Institute, 1-1-1 Koto, Sayo-cho, Sayo-Gun, Hyogo, 679-5148, Japan.
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Higuchi
mesh_terms: D001222:Aspartate Kinase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D002826:Chorismate Mutase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D003541:Cystathionine beta-Synthase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D000072417:Protein Domains; D016963:Thermus thermophilus / Q000201:enzymology / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; D001222:Aspartate Kinase; D003541:Cystathionine beta-Synthase; D002826:Chorismate Mutase
keywords: ACT domain; CBS domain; Crystal structure; Gene-annotation; Hypothetical protein; Thermus thermophilus HB8