MSMEG_2432 of Mycobacterium smegmatis mc2155 is a dual function enzyme that exhibits DD-carboxypeptidase and ß-lactamase activities.
Microbiology (Reading)
; 166(6): 546-553, 2020 06.
Article
em En
| MEDLINE
| ID: mdl-32301689
Mycobacterial peptidoglycan (PG) is an unsolved puzzle due to its complex structure and involvement of multiple enzymes in the process of its remodelling. dd-Carboxypeptidases are low molecular mass penicillin-binding proteins (LMM-PBPs) that catalyzes the cleavage of terminal d-Ala of muramyl pentapeptide branches and thereby helps in the PG remodelling process. Here, we have assigned the function of a putative LMM-PBP, MSMEG_2432 of Mycobacterium smegmatis, by showing that it exhibits both dd-CPase and ß-lactamase activities. Like conventional dd-CPase (PBP5 from E. coli), upon ectopic complementation in a deformed seven PBP deletion mutant of E. coli, MSMEG_2432 has manifested its ability to restore ~75â% of the cell population to their normal rod shape. Further, in vitrodd-CPase assay has confirmed its ability to release terminal d-Ala from the synthetic tripeptide and the peptidoglycan mimetic pentapeptide substrates ending with d-Ala-d-Ala. Also, elevated resistance against penicillins and cephalosporins upon ectopic expression of MSMEG_2432 suggests the presence of ß-lactamase activity, which is further confirmed in vitro through nitrocefin hydrolysis assay. Moreover, it is found apparent that D169A substitution in MSMEG_2432 influences both of its in vivo and in vitrodd-CPase and ß-lactamase activities. Thus, we infer that MSMEG_2432 is a dual function enzyme that possesses both dd-CPase and ß-lactamase activities.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteínas de Bactérias
/
Beta-Lactamases
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Carboxipeptidases
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Mycobacterium smegmatis
Idioma:
En
Revista:
Microbiology (Reading)
Assunto da revista:
MICROBIOLOGIA
Ano de publicação:
2020
Tipo de documento:
Article
País de afiliação:
Estados Unidos