Immunological characterization of an Escherichia coli strain which is lacking cytochrome d.

The isolated membranes from an Escherichia coli mutant strain which lacks spectroscopically detectable levels of cytochromes d, a1, and b558 also have abnormally low levels of N,N,N',N'-tetramethyl-p-phenylenediamine oxidase activity. In this paper, it is shown that the material previously identified as the N,N,N',N'-tetramethyl-p-phenylenediamine oxidase is, in fact, the two-subunit cytochrome d complex. Antisera directed against the native cytochrome d complex as well as against each of two subunits apparent on sodium dodecyl sulfate-polyacrylamide gels were used to show that the mutant strain lacks both subunits of the cytochrome d complex. Introduction of F-prime F152 into the mutant strain restored the two subunits along with the spectroscopic and enzymatic activity associated with the cytochrome d complex.