title: Investigation of the essentiality of glutamate racemase in Mycobacterium smegmatis.
abstract: The mycobacterial cell wall frequently has been used as a target for drug development, and d-glutamate, synthesized by glutamate racemase (MurI), is an important component of peptidoglycan. While the essentiality of the murI gene has been shown in several bacterial species, including Escherichia coli, Bacillus anthracis, and Streptococcus pneumoniae, studies in mycobacteria have not yet provided definitive results. This study aimed to determine whether murI is indeed essential and can serve as a possible target for structure-aided drug design. We have achieved this goal by creating a ΔmurI strain of Mycobacterium smegmatis, a close relative of Mycobacterium tuberculosis. The deletion of the murI gene in M. smegmatis could be achieved only in minimal medium supplemented with D-glutamate, demonstrating that MurI is essential for growth and that glutamate racemase is the only source of D-glutamate for peptidoglycan synthesis in M. smegmatis.
authors.affiliation: Department of Biochemistry, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand.
authors.forename: Yang
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Biochemistry, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand.
authors.forename: Roman
authors.initials: R
authors.lastname: Mortuza
authors.affiliation: Department of Biochemistry, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand.
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Milligan
authors.affiliation: Department of Microbiology and Immunology, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand.
authors.forename: Sieu L
authors.initials: SL
authors.lastname: Tran
authors.affiliation: Baylor College of Medicine, Section of Pediatric Tropical Medicine, Houston, Texas, USA.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Strych
authors.affiliation: Department of Microbiology and Immunology, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand.
authors.forename: Gregory M
authors.initials: GM
authors.lastname: Cook
authors.affiliation: Department of Biochemistry, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand kurt.krause@otago.ac.nz.
authors.forename: Kurt L
authors.initials: KL
authors.lastname: Krause
mesh_terms: D000591:Amino Acid Isomerases / Q000235:genetics* / Q000378:metabolism*; D002473:Cell Wall / Q000378:metabolism; D003470:Culture Media / Q000737:chemistry; D017353:Gene Deletion; D020043:Genes, Essential; D018698:Glutamic Acid / Q000378:metabolism; D020102:Mycobacterium smegmatis / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development*; D010457:Peptidoglycan / Q000378:metabolism
chemical_list: D003470:Culture Media; D010457:Peptidoglycan; D018698:Glutamic Acid; D000591:Amino Acid Isomerases; C062292:glutamate racemase