Variations within Class-A β-Lactamase Physiochemical Properties Reflect Evolutionary and Environmental Patterns, but not Antibiotic Specificity
Figure 1
Significant β-lactamase residues and its electrostatic characterization.
(a) Structure of a Class-A β-lactamase enzyme. The active site is located at the domain interface. The catalytic residue Ser-70 is shown in red. Other catalytic residues are shown in orange, whereas the Ω-loop is shown in blue at the top. Residues that maintain the structural integrity are shown in cyan. (b) Electrostatic potential values of ±1 kcal/mol are mapped to the protein surface. Red indicates negative potential, while blue indicates positive potential. The structure is oriented to display a patch of negative potential at the interface of the Ω-loop and helices H3, H4 and H6 that is conserved within the TEM/SHV enzymes. (c) Conserved electrostatic networks (cf. Figure 2b) are mapped to a BL structure. Green colored spheres represent α-carbons of residues interacting strongly with catalytic residues, which are highlighted in orange.