title: Structure-based functional classification of hypothetical protein MTH538 from Methanobacterium thermoautotrophicum.
abstract: The structure of MTH538, a previously uncharacterized hypothetical protein from Methanobacterium thermoautotrophicum, has been determined by NMR spectroscopy. MTH538 is one of numerous structural genomics targets selected in a genome-wide survey of uncharacterized sequences from this organism. MTH538 is a so-called singleton, a sequence not closely related to any other (known) sequences. The structure of MTH538 closely resembles the known structures of receiver domains from two component response regulator systems, such as CheY, and is similar to the structures of flavodoxins and GTP-binding proteins. Tests on MTH538 for characteristic activities of CheY and flavodoxin were negative. MTH538 did not become phosphorylated in the presence of acetyl phosphate and Mg(2+), although it appeared to bind Mg(2+). MTH538 also did not bind flavin mononucleotide (FMN) or coenzyme F(420). Nevertheless, sequence and structure parallels between MTH538/CheY and two families of ATPase/phosphatase proteins suggest that MTH538 may have a role in a phosphorylation-independent two-component response regulator system.
authors.affiliation: Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, EMSL 2569 K8-98, Richland, WA 99352, USA.
authors.forename: J R
authors.initials: JR
authors.lastname: Cort
authors.forename: A
authors.initials: A
authors.lastname: Yee
authors.forename: A M
authors.initials: AM
authors.lastname: Edwards
authors.forename: C H
authors.initials: CH
authors.lastname: Arrowsmith
authors.forename: M A
authors.initials: MA
authors.lastname: Kennedy
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000378:metabolism; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D019295:Computational Biology; D005486:Flavin Mononucleotide / Q000378:metabolism; D005418:Flavodoxin / Q000737:chemistry / Q000378:metabolism; D008274:Magnesium / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism; D017014:Methanobacterium / Q000737:chemistry* / Q000235:genetics; D000072236:Methyl-Accepting Chemotaxis Proteins; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D010744:Phosphoric Monoester Hydrolases / Q000737:chemistry / Q000378:metabolism; D010766:Phosphorylation; D011485:Protein Binding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D012256:Riboflavin / Q000031:analogs & derivatives* / Q000378:metabolism; D016415:Sequence Alignment; D013329:Structure-Activity Relationship
chemical_list: D001426:Bacterial Proteins; D005418:Flavodoxin; C413706:MTH538 protein, Methanobacterium thermoautotrophicum; D008565:Membrane Proteins; D000072236:Methyl-Accepting Chemotaxis Proteins; C015084:coenzyme F420; D005486:Flavin Mononucleotide; D010744:Phosphoric Monoester Hydrolases; D000251:Adenosine Triphosphatases; D008274:Magnesium; D012256:Riboflavin