FIG 7.

When the MB_076 binding with KPC-2 (A) is compared with the MB_076 binding with CTX-M-96 (B) after 500 ps molecular modeling simulation, the main difference is H-bond interactions of the boronic tetrahedral geometry, with more H bonds present in CTX-M-96 than in KPC-2. The notable interaction is the direct ionic bond of the carboxyl group with K234 residue. The hydrophobic interactions with MB_076 S-thiadiazole ring are present for both KPC-2 (W105) and CTX-M-96 (Y105). However, as for the S02030 complex, W105 in KPC-2 seems to be engaged in hydrophobic interactions with L167 for this complex, resulting in a slightly higher affinity of MB_076 for CTX-M-96.