Improved antimicrobial spectrum of the N-acetylmuramoyl-l-alanine amidase from Latilactobacillus sakei upon LysM domain deletion

The objective of this work was to evaluate the effect of LysM domain deletion on antibacterial activity as well the biochemical characterization of each recombinant protein. AmiC and AmiLysM4 were expressed inEscherichia coli BL21. Using a zymography method, two bands with lytic activity were observed, which were confirmed by LC –MS/MS analysis, with molecular masses of 71 kDa (AmiC) and 66 kDa (AmiLysM4). The recombinant proteins were active againstListeria innocua andStaphylococcus aureus strains. The inhibitory spectrum of AmiLysM4 was broader than AmiC as it showed inhibition ofLeuconostoc mesenteroides andWeissella viridescens, both microorganisms associated with food decomposition. Optimal temperature and pH values were determined for both proteins usingl-alanine-p-nitroanilide hydrochloride as a substrate for N-acetylmuramoyl-l-alanine amidase activity. Both proteins showed similar maximum activity values for pH (8) and temperature (50  °C). Furthermore, structural predictions did not show differences for the catalytic region, but differences were found for the region called 2dom-AmiLysM4, which includes 4 of the 5 LysM domains. Therefore, modification of the LysM domain offers new tools for the development of novel food biopres ervatives.Graphic abstract
Source: World Journal of Microbiology and Biotechnology - Category: Microbiology Source Type: research