Understanding High Specificity of Acquired 16s Rrna Methyltransferases of AMR Pathogens

Abstract

Antimicrobial Resistance is one of the major causes of concern around the world and is projected to be even more prevalent in years to come. The study of this ability of bacteria to tolerate the presence of the existent antimicrobials by different mechanism, is important for understanding the cause of this problem. This study is focused on one such resistance mechanism, i.e. the alteration of target site of antimicrobials, specifically aminoglycosides that use 30S subunit of rRNA as a substrate for their antimicrobial action. The 16S RNA Methyl Transferases alter the A site of translation by methylation and provide resistance to the bacteria. These RMTases consist of an N-terminal domain and a C terminal domain each. In this study, three different RMTases namely, NpmA, ArmA and RmtA are studied as two different chimeras, namely, NpmAN_ArmAC and NpmAN_RmtAC in the hope of understanding the specificity of the domains towards ribosome binding (and methylation). The chimeras were constructed by joining the N-terminal domain of NpmA to the C-terminal domains of ArmA or RmtA. The effect of change in binding site of the RMTase was seen by quantifying the change in the tolerance of wild type strain to the new transformed strain. The protein expression of the newly constructed RMTases were also checked by different techniques.