Isolation of a Rhodobacter capsulatus mutant that lacks c-type cytochromes and excretes porphyrins.
A Rhodobacter capsulatus mutant lacking cytochrome oxidase activity was isolated by Tn5 mutagenesis. Difference spectroscopy of crude extracts and extracted c-type cytochromes demonstrated that this mutant completely lacked all c-type cytochromes. The strain did, however, synthesize normal amounts of b-type cytochromes and nonheme iron. This mutant also excreted large amounts of coproporphyrin and protoporphyrin and synthesized reduced amounts of bacteriochlorophyll, suggesting a link between the synthesis of c-type cytochromes and the expression of the tetrapyrrole biosynthetic pathway.
Biel
S W
SW
Department of Microbiology, Louisiana State University, Baton Rouge 70803.
Biel
A J
AJ
D003001:Cloning, Molecular; D003574:Cytochrome c Group / Q000235:genetics*; D003580:Cytochromes / Q000096:biosynthesis* / Q000302:isolation & purification; D004251:DNA Transposable Elements; D005798:Genes, Bacterial; D009154:Mutation; D011166:Porphyrins / Q000096:biosynthesis* / Q000302:isolation & purification; D015183:Restriction Mapping; D012241:Rhodopseudomonas / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism
D003574:Cytochrome c Group; D003580:Cytochromes; D004251:DNA Transposable Elements; D011166:Porphyrins