1jfu

CRYSTAL STRUCTURE OF THE SOLUBLE DOMAIN OF TLPA FROM BRADYRHIZOBIUM JAPONICUM

spinqualitylabelsall models 1jfu, resolution 1.60Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1jfu is a 2 chain structure with sequence from Bradyrhizobium japonicum. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.6Å Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function TLPA_BRADU Involved in cytochrome aa3 assembly. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed TlpA is an unusual thioredoxin-like protein present in the nitrogen-fixing soil bacterium Bradyrhizobium japonicum. A hydrophobic N-terminal transmembrane domain anchors it to the cytoplasmic membrane, whereby the hydrophilic thioredoxin domain becomes exposed to the periplasmic space. There, TlpA catalyses an essential reaction, probably a reduction, in the biogenesis of cytochrome aa(3). The soluble thioredoxin domain (TlpA(sol)), devoid of the membrane anchor, was purified and crystallized. Oxidized TlpA(sol) crystallized as a non-covalent dimer in the space group P2(1)2(1)2(1). The X-ray structure analysis was carried out by isomorphous replacement using a xenon derivative. This resulted in a high-resolution (1.6 A) three-dimensional structure that displayed all of the features of a classical thioredoxin fold. A number of peculiar structural details were uncovered: (i) Only one of the two active-site-cysteine sulphurs (Cys72, the one closer to the N terminus) is exposed on the surface, making it the likely nucleophile for the reduction of target proteins. (ii) TlpA(sol) possesses a unique structural disulphide bond, formed between Cys10 and Cys155, which connects an unprecedented N-terminal alpha helix with a beta sheet near the C terminus. (iii) An insertion of about 25 amino acid residues, not found in the thioredoxin prototype of Escherichia coli, contributes only marginally to the thioredoxin fold, but forms an extra, surface-exposed alpha helix. This region plus another surface-exposed stretch (-Ile-Gly-Arg-Ala-), which is absent even in the closest TlpA relatives, might be considered as specificity determinants for the recognition of target proteins in the periplasm. The TlpA(sol) structure paves the way towards unraveling important structure-function relationships by rational mutagenesis. Structure of the soluble domain of a membrane-anchored thioredoxin-like protein from Bradyrhizobium japonicum reveals unusual properties.,Capitani G, Rossmann R, Sargent DF, Grutter MG, Richmond TJ, Hennecke H J Mol Biol. 2001 Aug 31;311(5):1037-48. PMID:11531338 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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