Sequential resonance assignments of oxidized high-potential iron-sulfur protein from Chromatium vinosum

Biochemistry. 1992 Feb 4;31(4):1234-44. doi: 10.1021/bi00119a037.

Abstract

2D NMR spectra of the high-potential iron-sulfur protein (HiPIP) from Chromatium vinosum have been used to obtain partial resonance assignments for the oxidized paramagnetic redox state of the protein. Sequence-specific assignments were made using NOESY and COSY spectra in H2O and D2O of the following backbone segments: Asn-5-Arg-33, Glu-39-Asp-45, Gly-55-Cys-63, Gly-68-Ala-78, and Leu-82-Gly-85. NOESY spectra with a spectral width wide enough to include the hyperfine-shifted resonances revealed numerous NOE contacts between these signals and those in the main envelope of the proton spectrum. With the aid of the X-ray crystal structure [Carter, C.W., Kraut, J., Freer, S. T., Xuong, N. H., Alden, R. A., & Bartsch, R. G. (1974) J. Biol. Chem. 249, 4212], these NOEs permitted seven of the nine hyperfine-shifted signals to be assigned to three of the cysteine residues liganded to the metal cluster (Cys-43, Cys-46, and Cys-77). The other two hyperfine-shifted signals produced no detectable NOEs to other resonances in the spectrum and were tentatively assigned to the remaining cysteinyl ligand (Cys-63). These assignments, in conjunction with recent theoretical models of the electronic structure of the Fe4S4 cluster [Noodleman, L. (1988) Inorg. Chem. 27, 3677; Bertini, I., Briganti, F., Luchinat, C., Scozzafava, A., & Sola, M. (1991) J. Am. Chem. Soc. 113, 1237], indicate that the iron atoms coordinated to Cys-63 and Cys-77 are those of the mixed-valence Fe(3+)-Fe2+ pair whereas Cys-43 and Cys-46 are ligands to the Fe(3+)-Fe3+ metal pair.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Bacterial Proteins / chemistry
  • Chromatium / chemistry*
  • Cysteine / chemistry
  • Iron-Sulfur Proteins / chemistry*
  • Magnetic Resonance Spectroscopy
  • Molecular Sequence Data
  • Oxidation-Reduction
  • Peptides / chemistry
  • Protein Conformation
  • Tryptophan / chemistry
  • Tyrosine / chemistry

Substances

  • Bacterial Proteins
  • Iron-Sulfur Proteins
  • Peptides
  • Tyrosine
  • Tryptophan
  • Cysteine