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Sulfite reductase structure at 1.6 A: evolution and catalysis for reduction of inorganic anions.

Publication ,  Journal Article
Crane, BR; Siegel, LM; Getzoff, ED
Published in: Science
October 6, 1995

Fundamental chemical transformations for biogeochemical cycling of sulfur and nitrogen are catalyzed by sulfite and nitrite reductases. The crystallographic structure of Escherichia coli sulfite reductase hemoprotein (SiRHP), which catalyzes the concerted six-electron reductions of sulfite to sulfide and nitrite to ammonia, was solved with multiwavelength anomalous diffraction (MAD) of the native siroheme and Fe4S4 cluster cofactors, multiple isomorphous replacement, and selenomethionine sequence markers. Twofold symmetry within the 64-kilodalton polypeptide generates a distinctive three-domain alpha/beta fold that controls cofactor assembly and reactivity. Homology regions conserved between the symmetry-related halves of SiRHP and among other sulfite and nitrite reductases revealed key residues for stability and function, and identified a sulfite or nitrite reductase repeat (SNiRR) common to a redox-enzyme superfamily. The saddle-shaped siroheme shares a cysteine thiolate ligand with the Fe4S4 cluster and ligates an unexpected phosphate anion. In the substrate complex, sulfite displaces phosphate and binds to siroheme iron through sulfur. An extensive hydrogen-bonding network of positive side chains, water molecules, and siroheme carboxylates activates S-O bonds for reductive cleavage.

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Published In

Science

DOI

ISSN

0036-8075

Publication Date

October 6, 1995

Volume

270

Issue

5233

Start / End Page

59 / 67

Location

United States

Related Subject Headings

  • Sulfites
  • Sulfite Reductase (NADPH)
  • Protein Structure, Tertiary
  • Protein Structure, Secondary
  • Protein Folding
  • Protein Conformation
  • Oxidoreductases Acting on Sulfur Group Donors
  • Oxidation-Reduction
  • Molecular Sequence Data
  • Models, Molecular
 

Citation

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Crane, B. R., Siegel, L. M., & Getzoff, E. D. (1995). Sulfite reductase structure at 1.6 A: evolution and catalysis for reduction of inorganic anions. Science, 270(5233), 59–67. https://doi.org/10.1126/science.270.5233.59
Crane, B. R., L. M. Siegel, and E. D. Getzoff. “Sulfite reductase structure at 1.6 A: evolution and catalysis for reduction of inorganic anions.Science 270, no. 5233 (October 6, 1995): 59–67. https://doi.org/10.1126/science.270.5233.59.
Crane BR, Siegel LM, Getzoff ED. Sulfite reductase structure at 1.6 A: evolution and catalysis for reduction of inorganic anions. Science. 1995 Oct 6;270(5233):59–67.
Crane, B. R., et al. “Sulfite reductase structure at 1.6 A: evolution and catalysis for reduction of inorganic anions.Science, vol. 270, no. 5233, Oct. 1995, pp. 59–67. Pubmed, doi:10.1126/science.270.5233.59.
Crane BR, Siegel LM, Getzoff ED. Sulfite reductase structure at 1.6 A: evolution and catalysis for reduction of inorganic anions. Science. 1995 Oct 6;270(5233):59–67.
Journal cover image

Published In

Science

DOI

ISSN

0036-8075

Publication Date

October 6, 1995

Volume

270

Issue

5233

Start / End Page

59 / 67

Location

United States

Related Subject Headings

  • Sulfites
  • Sulfite Reductase (NADPH)
  • Protein Structure, Tertiary
  • Protein Structure, Secondary
  • Protein Folding
  • Protein Conformation
  • Oxidoreductases Acting on Sulfur Group Donors
  • Oxidation-Reduction
  • Molecular Sequence Data
  • Models, Molecular