Crystal structure of cambialistic superoxide dismutase from porphyromonas gingivalis

Eur J Biochem. 2000 Jun;267(12):3487-95. doi: 10.1046/j.1432-1327.2000.01373.x.

Abstract

The crystal structure of cambialistic superoxide dismutase (SOD) from Porphyromonas gingivalis, which exhibits full activity with either Fe or Mn at the active site, has been determined at 1.8-A resolution by molecular replacement and refined to a crystallographic R factor of 17.9% (Rfree 22.3%). The crystals belong to the space group P212121 (a = 75.5 A, b = 102.7 A, c = 99.6 A) with four identical subunits in the asymmetric unit. Each pair of subunits forms a compact dimer, but not a tetramer, with 222 point symmetry. Each subunit has 191 amino-acid residues most of which are visible in electron density maps, and consists of seven alpha helices and one three-stranded antiparallel beta sheet. The metal ion, a 3 : 1 mixture of Fe and Mn, is coordinated with five ligands (His27, His74, His161, Asp157, and water) arranged at the vertices of a trigonal bipyramid. Although the overall structural features, including the metal coordination geometry, are similar to those found in other single-metal containing SODs, P. gingivalis SOD more closely resembles the dimeric Fe-SODs from Escherichia coli rather than another cambialistic SOD from Propionibacterium shermanii, which itself is rather similar to other tetrameric SODs.

MeSH terms

  • Amino Acid Sequence
  • Catalytic Domain
  • Crystallography, X-Ray
  • Metals / metabolism
  • Models, Molecular
  • Molecular Sequence Data
  • Polyethylene Glycols / chemistry
  • Porphyromonas gingivalis / enzymology*
  • Protein Conformation
  • Protein Folding
  • Protein Structure, Quaternary
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Solutions
  • Superoxide Dismutase / chemistry*
  • Superoxide Dismutase / genetics
  • Superoxide Dismutase / metabolism*

Substances

  • Metals
  • Recombinant Proteins
  • Solutions
  • Polyethylene Glycols
  • Superoxide Dismutase