Extragenic suppression of the requirement for diaminopimelate in diaminopimelate auxotrophs of Mycobacterium smegmatis

Mycobacteria, like many prokaryotes, have a pepticloglycan with peptides composed of L-alanine (or glycine), D-iso-glutamine, mesodiaminopimelate, and D-alanine. We sought to study mycobacterial peptidoglycan biosynthesis by constructing diaminopimelate (DAP) auxotrophs of Mycobaeterium smegmatis and then isolating spontaneous mutants of these auxotrophs that can grow in the absence of DAP. Here we report the isolation and characterization of seven classes of spontaneous M. smegmatis mutants with extragenic mutations that can suppress the DAP requirement of DAP auxotrophs. (C) 2003 Published by Elsevier Science B.V. on behalf of the Federation of European Microbiological Societies.