title: Temperature-sensitive mutants of Escherichia coli K-12 with low activities of the L-alanine adding enzyme and the D-alanyl-D-alanine adding enzyme.
abstract: A number of properties of temperature-sensitive mutants in murein synthesis are described. The mutants grow at 30 C but lyse at 42 C. One mutant possesses a temperature-sensitive d-alanyl-d-alanine adding enzyme, has an impaired rate of murein synthesis in vivo at both 30 and 42 C, and contains elevated levels of uridine diphosphate-N-acetyl-muramyl-tripeptide (UDP-MurNAc-l-Ala-d-Glu-m-diaminopimelic acid) at 42 C. The other mutant possesses an l-alanine adding enzyme with a very low in vitro activity at both 30 and 42 C. Its in vivo rate of murein synthesis is almost normal at 30 C but is much less at 42 C. When the murein precursors were isolated after incubation of the cells in the presence of (14)C-l-alanine, they contained only a fraction of the radioactivity that could be obtained from a wild-type strain. A genetic nomenclature for genes concerned with murein synthesis is proposed.
mesh_terms: D000085:Acetates; D000409:Alanine / Q000378:metabolism; D002247:Carbon Isotopes; D002701:Chloramphenicol / Q000494:pharmacology; D004151:Dipeptides; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology* / Q000254:growth & development / Q000378:metabolism; D005796:Genes; D005827:Genetics, Microbial; D005944:Glucosamine / Q000096:biosynthesis; D008025:Ligases; D009154:Mutation; D009702:Nucleoside Diphosphate Sugars / Q000096:biosynthesis; D010452:Peptide Biosynthesis; D010457:Peptidoglycan / Q000096:biosynthesis; D013696:Temperature; D013997:Time Factors; D014500:Uracil Nucleotides
chemical_list: D000085:Acetates; D002247:Carbon Isotopes; D004151:Dipeptides; D009702:Nucleoside Diphosphate Sugars; D010457:Peptidoglycan; D014500:Uracil Nucleotides; D002701:Chloramphenicol; D008025:Ligases; D005944:Glucosamine; D000409:Alanine