SUMMARY: A mutant K12 has been isolated affected in a gene, designated , distinct from the three previously described loci involved in the synthesis of assembly of the cytochrome oxidase complex. The mutant, obtained by nitrosoguanidine mutagenesis, lacks the spectroscopically detectable components of this oxidase, namely cytochromes , and Cytochrome oxidase is the sole CO-binding cytochrome in membranes of the mutant, but the soluble haemoprotein -590 and catalase activity appear unaffected. Discrimination between Cyd and Cyd strains is facilitated by the development of a defined low-phosphate medium that allows the inclusion of Zn as well as azide, inhibitors of respiratory electron transfer particularly via cytochrome Mapping with F-prime factors and by P1 cotransductional frequencies shows the mutation to map near 19-3 min on the chromosome, distinct from , which maps at 18·9 min. The gene order in this region was tested in a three-factor cross and demonstrates the order (YYC199), consistent with cotransduction frequencies.


Article metrics loading...

Loading full text...

Full text loading...


Most cited this month Most Cited RSS feed

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error