Superoxide dismutase from Bacillus stearothermophilus. Complete amino acid sequence of a manganese enzyme

Abstract

Superoxide dismutase from the thermophilic bacterium B. stearothermophilus is dimeric with a MW of 45,487. It contains 1 atom of Mn (III)/dimeric molecule. The subunits are identical, and the primary structure comprising 203 amino acids was determined. The enzyme is identical in 60% of its residues with the Escherichia coli B Mn enzyme. Neither Mn enzyme has significant homology with the Cu/Zn superoxide dismutase from bovine erythrocytes. The secondary structures of the Mn enzymes predicted by McLachlan''s method indicate that the 8-stranded .beta. barrel of the Cu/Zn enzyme is absent from the Mn enzymes.