A putative low-molecular mass (LMM) XXXX -binding protein (PBP) of @entity7666 exhibits prominent physiological characters of DD-Carboxypeptidase and @entity14474 .

@entity3405 @entity114 @entity14474 @entity7666 @entity526 @entity71672
UNASSIGNED: DD-Carboxypeptidases (DD-CPases) are low-molecular mass (LMM) @entity114 -binding proteins (PBPs) that are mainly involved in the peptidoglycan remodelling, but little is known about the DD-CPases of mycobacteria. In this study a putative DD-CPase of @entity7666 , MSMEG_2433 has been characterized. The gene for the membrane-bound form of MSMEG_2433 was cloned and expressed in @entity526 in its active form as revealed by its ability to bind to the @entity71672 (fluorescent @entity114 ). Interestingly, in vivo expression of MSMEG_2433 could restore the cell-shape oddities of the septuple PBP mutant of @entity526 , which was a prominent physiological character of DD-CPases. Moreover, expression of MSMEG_2433 in trans, elevated the @entity3405 resistance in the PBP deletion mutants (   dacAdacC) of @entity526 that strengthened its physiology as a DD-CPase. To confirm the biochemical reason behind such physiological behaviours, soluble form of MSMEG_2433 (sMSMEG_2433) was created, expressed and purified. In agreement to the observed physiological phenomena, the sMSMEG_2433 exhibited the DD-CPase activity against artificial and peptidoglycan-mimetic DD-CPase substrate. To our surprise, enzymatic analyses of MSMEG_2433 revealed the efficient deacylation for @entity3405 substrates at physiological pH, which is a unique character of beta-lactamases. In addition to the MSMEG_2433 active-site that favours DD-CPase activity, in silico analyses also predicted the presence of an omega-loop like region in MSMEG_2433, which is an important determinant of its @entity14474 activity. Based on the in vitro, in vivo and in silico studies we conclude that MSMEG_2433 is a dual enzyme, possessing both DD-CPase and @entity14474 activities.
