RRC ID 30110
Author Nakayashiki T, Nishimura K, Tanaka R, Inokuchi H.
Title Partial inhibition of protein synthesis accelerates the synthesis of porphyrin in heme-deficient mutants of Escherichia coli.
Journal Mol Gen Genet
Abstract Mutants of Escherichia coli defective in the HemA protein grow extremely poorly as the result of heme deficiency. A novel hemA mutant was identified whose rate of growth was dramatically enhanced by addition to the medium of low concentrations of translational inhibitors, such as chloramphenicol and tetracycline. This mutant (H110) carries mutation at position 314 in the hemA gene, which resulted in diminished activity of the encoded protein. Restoration of growth of H110 upon addition of the drugs mentioned above was due to activation of the synthesis of porphyrin. However, this activation was not characteristic exclusively of cells with this mutant hemA gene since it was also observed in a heme-deficient strain bearing the wild-type hemA gene. The activation did not depend on the promoter activity of the hemA gene, as indicated by studies with fusion genes. It appears that partial inhibition of protein synthesis via inhibition of peptidyltransferase can promote the synthesis of porphyrin by providing an increased supply of glutamyl-tRNA for porphyrin synthesis. Glutamyl-tRNA is the common substrate for peptidyltransferase and HemA.
Volume 249(2)
Pages 139-46
Published 1995-11-15
DOI 10.1007/BF00290359
PMID 7500934
MeSH Aldehyde Oxidoreductases / biosynthesis Aldehyde Oxidoreductases / genetics* Aldehyde Oxidoreductases / metabolism* Amino Acid Sequence Base Sequence Chloramphenicol / pharmacology Cloning, Molecular DNA Primers Escherichia coli / drug effects Escherichia coli / genetics* Escherichia coli / metabolism* Genes, Bacterial Genotype Molecular Sequence Data Point Mutation* Polymerase Chain Reaction Porphyrins / biosynthesis* Protein Synthesis Inhibitors / pharmacology* Recombinant Proteins / biosynthesis Sequence Homology, Amino Acid Tetracycline / pharmacology beta-Galactosidase / biosynthesis
Times Cited 26
Prokaryotes E. coli IH77