Kupper, M.B.M.B.KupperHerzog, K.K.HerzogBennink, S.S.BenninkSchlomer, P.P.SchlomerBogaerts, P.P.BogaertsGlupczynski, Y.Y.GlupczynskiFischer, R.R.FischerBebrone, C.C.BebroneHoffmann, K.M.K.M.Hoffmann2022-03-052022-03-052015https://publica.fraunhofer.de/handle/publica/24207010.1111/febs.13283The metallo-beta-lactamase VIM-31 differs from VIM-2 by only two Tyr224-His and His252Arg substitutions. Located close to the active site, the Tyr224His substitution is also present in VIM-1, VIM-4, VIM-7 and VIM-12. The VIM-31 variant was reported in 2012 from Enterobacter cloacae and kinetically characterized. It exhibits globally lower catalytic efficiencies than VIM-2. In the present study, we report the three-dimensional structures of VIM-31 in its native (reduced) and oxidized forms. The so-called 'flapping-loop' (loop 1) and loop 3 of VIM-31 were not positioned as in VIM-2 but instead were closer to the active site as in VIM-4, resulting in a narrower active site in VIM-31. Also, the presence of His224 in VIM-31 disrupts hydrogen-bonding networks close to the active site. Moreover, a third zinc-binding site, which also exists in VIM-2 structures, could be identified as a structural explanation for the decreased activity of VIM-MBLs at high zinc concentrations.en572journal article