title: Crystal structure of MJ1247 protein from M. jannaschii at 2.0 A resolution infers a molecular function of 3-hexulose-6-phosphate isomerase.
abstract: The crystal structure of the hypothetical protein MJ1247 from Methanococccus jannaschii at 2 A resolution, a detailed sequence analysis, and biochemical assays infer its molecular function to be 3-hexulose-6-phosphate isomerase (PHI). In the dissimilatory ribulose monophosphate (RuMP) cycle, ribulose-5-phosphate is coupled to formaldehyde by the 3-hexulose-6-phosphate synthase (HPS), yielding hexulose-6-phosphate, which is then isomerized to fructose-6-phosphate by the enzyme 3-hexulose-6-phosphate isomerase. MJ1247 is an alpha/beta structure consisting of a five-stranded parallel beta sheet flanked on both sides by alpha helices, forming a three-layered alpha-beta-alpha sandwich. The fold represents the nucleotide binding motif of a flavodoxin type. MJ1247 is a tetramer in the crystal and in solution and each monomer has a folding similar to the isomerase domain of glucosamine-6-phosphate synthase (GlmS).
authors.affiliation: Physical Biosciences Division, Lawrence Berkeley National Laboratory and Department of Chemistry, University of California, Berkeley, 94720, USA. almartinez@unav.es
authors.forename: Luis Alfonso
authors.initials: LA
authors.lastname: Martinez-Cruz
authors.forename: Matthias K
authors.initials: MK
authors.lastname: Dreyer
authors.forename: David C
authors.initials: DC
authors.lastname: Boisvert
authors.forename: Hisao
authors.initials: H
authors.lastname: Yokota
authors.forename: Maria Luz
authors.initials: ML
authors.lastname: Martinez-Chantar
authors.forename: Rosalind
authors.initials: R
authors.lastname: Kim
authors.forename: Sung-Hou
authors.initials: SH
authors.lastname: Kim
mesh_terms: D000595:Amino Acid Sequence; D019843:Archaeal Proteins / Q000737:chemistry* / Q000378:metabolism*; D001426:Bacterial Proteins / Q000737:chemistry; D001665:Binding Sites; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000201:enzymology; D005956:Glucose-6-Phosphate Isomerase / Q000737:chemistry / Q000378:metabolism*; D006600:Hexosephosphates / Q000378:metabolism; D017017:Methanococcus / Q000201:enzymology*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D013237:Stereoisomerism; D013329:Structure-Activity Relationship; D005945:Glutamine-Fructose-6-Phosphate Transaminase (Isomerizing)
chemical_list: D019843:Archaeal Proteins; D001426:Bacterial Proteins; D005956:Glucose-6-Phosphate Isomerase; D006600:Hexosephosphates; C453580:3-hexulose-6-phosphate isomerase; C000731191:component S, glutamate mutase protein, Bacteria; D005945:Glutamine-Fructose-6-Phosphate Transaminase (Isomerizing)