Development of irreversible inhibitors forβ-lactam inactived enzyme, metallo-β-lactamase

IMP-1金属β-内酰胺酶是一种双核锌(II)酶，能催化包括碳青霉烯类在内的大多数β-内酰胺类抗生素的水解和失活，并参与了病原菌对抗生素产生耐药的机制之一。用紫外可见光谱研究了锌离子和钴离子对含有双核金属结合位(锌1和锌2位)的金属β内酰胺酶APO-IMP-1辅酶的金属选择性。测定了含1当量的apo-IMP-1的紫外-可见光谱。Co(II)和1当量。结果表明，与Co(II)相比，锌(II)对锌离子具有更高的择优作用。用Co(II)取代的金属β-内酰胺酶和紫外-可见光谱研究了金属酶IMP-1与巯基乙酸的相互作用。提出了Co(II)或Zn(II)与apo-IMP-1中二核金属结合部位以及巯基乙酸与Co(II)取代的IMP-1可能的金属结合方式。

IMP-1 metallo-β-lactamase is a dinuclear Zn(II) enzyme that catalyzes the hydrolysis and inactivation of mostβ-lactams including carbapenems, and is involved in one of the mechanisms for generating clinical resistance to antibiotics in pathogenic bacteria. We investigated the metal preferences of Zn(II) and Co(II) for the apo-enzyme of IMP-1 metallo-β-lactamase, apo-IMP-1, which contains a dinuclear metal binding site(the Zn1 and Zn2 sites), by UV-visible spectroscopy. The UV-visible spectrum of apo-IMP-1 containing 1 equiv. of Co(II) and 1 equiv. of Zn(II) showed a high preference of Zn(II) for the Zn1 site compared to Co(II). The interaction of IMP-1 metallo-β-lactamase with mercaptoacetic acid was also investigated using Co(II)-substituted IMP-1 and UV-visible spectroscopy. Possible metal binding modes of Co(II) or Zn(II) to the dinucelar metal binding site in apo-IMP-1 and of mercaptoacetic acid to Co(II)-substituted IMP-1 are proposed.