Cloning, nucleotide sequence and characterization of a gene encoding superoxide dismutase from Campylobacter jejuni and Campylobacter coli

Abstract

Genes encoding superoxide dismutase (SOD: EC 1.15.1.1) were cloned from Campylobacter jejuni NCTC 11351 and Campylobacter coli UA585 by heterologous complementation of a SOD-deficient Escherichia coli mutant. Deletion analysis of the cloned C. jejuni DNA assigned the sod gene to a 1.2 kb insert and this contained an open reading frame of 660 bp. The deduced gene product of 220 amino acids was 71% identical to the E. coli iron-containing SOD and 60% identical to the E. coli manganese-containing SOD. The recombinant SOD was expressed at high levels in E. coli and protected a sodA sodB double mutant from the toxic effects of methyl viologen. Nucleotide sequence analysis of the corresponding gene from C. coli showed it to be 92% identical to that from C. jejuni.