Genes involved in meso-diaminopimelate synthesis in Bacillus subtilis: identification of the gene encoding aspartokinase I

Détails

ID Serval
serval:BIB_40E4407505F8
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Genes involved in meso-diaminopimelate synthesis in Bacillus subtilis: identification of the gene encoding aspartokinase I
Périodique
J Gen Microbiol
Auteur(s)
Roten  C. A., Brandt  C., Karamata  D.
ISSN
0022-1287 (Print)
Statut éditorial
Publié
Date de publication
04/1991
Volume
137
Numéro
4
Pages
951-62
Notes
Journal Article --- Old month value: Apr
Résumé
Thermosensitive mutants of Bacillus subtilis deficient in peptidoglycan synthesis were screened for mutations in the meso-diaminopimelate (LD-A2pm) metabolic pathway. Mutations in two out of five relevant linkage groups, lssB and lssD, were shown to induce, at the restrictive temperature, a deficiency in LD-A2pm synthesis and accumulation of UDP-MurNAc-dipeptide. Group lssB is heterogeneous; it encompasses mutations that confer deficiency in the deacylation of N-acetyl-LL-A2pm and accumulation of this precursor. Accordingly, these mutations are assigned to the previously identified locus dapE. Mutations in linkage group lssD entail a thermosensitive aspartokinase 1. Therefore, they are most likely to affect the structural gene of this enzyme, which we propose to designate dapG. Mutation pyc-1476, previously reported to affect the pyruvate carboxylase, was shown to confer a deficiency in aspartokinase 1, not in the carboxylase, and to belong to the dapG locus, dapG is closely linked to spoVF, the putative gene of dipicolinate synthase. In conclusion, mutations affecting only two out of eight steps known to be involved in LD-A2pm synthesis were uncovered in a large collection of thermosensitive mutants obtained by indirect selection. We propose that this surprisingly restricted distribution of the thermosensitive dap mutations isolated so far is due to the existence, in each step of the pathway, of isoenzymes encoded by separate genes. The biological role of different aspartokinases was investigated with mutants deficient in dapE and dapG genes. Growth characteristics of these mutants in the presence of various combinations of aspartate family amino acids allow a reassessment of a metabolic channel hypothesis, i.e. the proposed existence of multienzyme complexes, each specific for a given end product.
Mots-clé
Aspartate Kinase/*genetics/metabolism Bacillus subtilis/enzymology/*genetics/growth & development Diaminopimelic Acid/*metabolism Genes, Bacterial Kinetics Linkage (Genetics) Mutation Peptidoglycan/metabolism Solubility Temperature Transformation, Bacterial
Pubmed
Web of science
Open Access
Oui
Création de la notice
24/01/2008 15:05
Dernière modification de la notice
08/05/2019 17:38
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