Isolation and characterization of an Escherichia coli mutant lacking cytochrome d terminal oxidase

Abstract

A screening procedure was devised which permitted the isolation of a cytochrome d-deficient mutant by its failure to oxidize the artificial electron donor N,N,N'',N''-tetramethyl-p-phenylenediamine. Cytochrome a1 and probably cytochrome b558 were also missing in the mutant. Growth and O2 uptake rates were similar for both parent and mutant strains. The strain lacking cytochrome d had an increased sensitivity to cyanide, indicating that cytochrome d confers some resistance to this respiratory inhibitor. The gene responsible for these phenotypes was named cyd and maps between tolA and sucB.