Antagonists Mo and Cu in a heterometallic cluster present on a novel protein (orange protein) isolated from Desulfovibrio gigas

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An orange-coloured protein (ORP) isolated from Desulfovibrio gigas, a sulphate reducer, has been previously shown by extended X-ray absorption fine structure (EXAFS) to contain a novel mixed-metal sulphide cluster of the type [S2MoS2CuS2MoS2] [J. Am. Chem. Soc. 122 (2000) 8321]. We report here the purification and the biochemical/ spectroscopic characterisation of this novel protein. ORP is a soluble monomeric protein (11.8 kDa). The cluster is non-covalently bound to the polypeptide chain. The presence of a MoS4 2- moiety in the structure of the cofactor contributes with a quite characteristic UV-Vis spectra, exhibiting an orange colour, with intense absorption peaks at 480 and 338 nm. Pure ORP reveals an Abs480/Abs338 ratio of 0.535. The gene sequence coding for ORP as well as the amino acid sequence was determined. The putative biological function of ORP is discussed.

Original languageEnglish
Pages (from-to)833-840
Number of pages8
JournalJournal of Inorganic Biochemistry
Issue number5
Publication statusPublished - 1 Jan 2004



  • Copper
  • Desulfovibrio gigas
  • Heterometallic cluster
  • Molybdenum
  • Tetrathiomolybdate

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