Article thumbnail
Location of Repository

Uroporphyrinogen III cosynthase-deficient mutant of Salmonella typhimurium LT2.

By A Săsárman and M Desrochers

Abstract

A new type of heme-deficient mutant of Salmonella typhimurium LT2 was isolated using neomycin. The mutant, designated as strain SASY74, accumulated uroporphyrin I and coproporphyrin I. Extracts of the mutant converted 5-aminolevulinic acid to uroporphyrin I. Extracts of the mutant SASY74 and of the uroporphyrinogen synthase-deficient mutant SASY32 complemented each other and converted, when incubated together, 5-aminolevulinic acid to protoporphyrin. This finding excludes the possibility that uroporphyrinogen I synthase in strain SASY74 is deficient in its cosynthase-binding ability. Hence, the most probable explanation for the accumulation of uroporphyrin I and coproporphyrin I by the mutant is the lack of the uroporphyrinogen III cosynthase activity. This mutant is the first isolated in bacteria with such deficiency, and the mutation is analogous, as far as porphyrin synthesis is concerned, to human congenital porphyria. Mapping of the corresponding gene (hemD) by conjugation and P22-mediated transduction suggests the following gene order on the chromosome: ilv....hemC, hemD, cya....metE. The hemC and hemD genes are probably adjacent; this is the first case in which two hem genes of Enterobacteriaceae are contiguous on the chromosomal map

Topics: Research Article
Year: 1976
OAI identifier: oai:pubmedcentral.nih.gov:232760
Provided by: PubMed Central
Sorry, our data provider has not provided any external links therefore we are unable to provide a link to the full text.

Suggested articles


To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.