Overexpression of a newly identified d-amino acid transaminase in Mycobacterium smegmatis complements glutamate racemase deletion.
Mol Microbiol
; 107(2): 198-213, 2018 01.
Article
em En
| MEDLINE
| ID: mdl-29134701
ABSTRACT
Glutamate racemase (MurI) has been proposed as a target for anti-tuberculosis drug development based on the inability of ΔmurI mutants of Mycobacterium smegmatis to grow in the absence of d-glutamate. In this communication, we identify ΔmurI suppressor mutants that are detected during prolonged incubation. Whole genome sequencing of these ΔmurI suppressor mutants identified the presence of a SNP, located in the promoter region of MSMEG_5795. RT-qPCR and transcriptional fusion analyses revealed that the ΔmurI suppressor mutant overexpressed MSMEG_5795 14-fold compared to the isogenic wild-type. MSMEG_5795, which is annotated as 4-amino-4-deoxychorismate lyase (ADCL) but which also has homology to d-amino acid transaminase (d-AAT), was expressed, purified and found to have d-AAT activity and to be capable of producing d-glutamate from d-alanine. Consistent with its d-amino acid transaminase function, overexpressed MSMEG_5795 is able to complement both ΔmurI deletion mutants and alanine racemase (Δalr) deletion mutants, thus confirming a multifunctional role for this enzyme in M. smegmatis.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Mycobacterium smegmatis
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D-Alanina Transaminase
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Isomerases de Aminoácido
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Oxo-Ácido-Liases
Idioma:
En
Ano de publicação:
2018
Tipo de documento:
Article