GENETIC AND BIOCHEMICAL ANALYSIS OF HEMIN DEPENDENT MUTANTS OF BACILLUS-SUBTILIS

  • 1 January 1975
    • journal article
    • research article
    • Vol. 22  (2) , 157-167
Abstract
Numerous porphyrin auxotrophic mutants were isolated from the 168 trpC2 strain of B. subtilis by selection with streptomycin. Some of them were supplemented with ALA [.delta.-amino-levulinic acid], while the majority grew only in the presence of hemin. Among the latter strains, the syntropism test allowed to distinguish 2 groups different in phenotype, i.e., feeders accumulating ALA and non-feeders accumulating instead of ALA other porphyrin intermediates. On the basis of transductional studies, feeders and non-feeders were divided into 2 and 4 groups, respectively. Biochemical investigation revealed that, wth 1 exception, 1 enzyme of the porphyrin biosynthesis was coordinated to each hem locus. The genes identified were hemB .fwdarw. ALA-dehydrase [EC 4.2.1.24]; hemC .fwdarw. PBG-deaminase; hemE .fwdarw. uroporphyrinogen decarboxylase; hemF .fwdarw. coproporphyrinogen oxidase; hemG .fwdarw. protoporphyrin-iron-chelatase.