Non-canonical H-bonds in β-lactamases: importance of C-H···π interactions.

β-Lactamase production is the common mechanism of resistance of β-lactam antibiotics. Knowledge of inter-residue interactions in protein structures increases our understanding of protein structure and stability. We have systematically analysed the contribution of C-H···π interactions to the stability of β-lactamases. Most of the interactions are long range and most of the interacting residues are evolutionarily conserved. The occurrence of C-H···π interactions in active sites and metal binding sites is very low in β-lactamases. Hence, C-H···π interactions are important determinants of stability in β-lactamases and they may not play a significant role in specificity. The results from this study provide valuable insights for understanding the stability patterns of β-lactamases and their relation to various other environmental preferences.