Rasia Rodolfo M, Ceolín Marcelo, Vila Alejandro J
Molecular Biology Division, Instituto de Biología Molecular y Celular Rosario, Consejo Nacional de Investigaciones Cientificas y Técnicas, University of Rosario, Suipacha 531, S2002LRK Rosario, Argentina.
Protein Sci. 2003 Jul;12(7):1538-46. doi: 10.1110/ps.0301603.
Metallo-beta-lactamases are zinc enzymes able to hydrolyze the four-membered ring of beta-lactam antibiotics, representing one of the latest generations of beta-lactamases. These enzymes belong to the zinc metallo-hydrolase family of the beta-lactamase fold. Enzymes belonging to this family have a bimetallic active site whose structure varies among different members by point substitutions of the metal ligands. In this work, we have grafted new metal ligands into the metal binding site of BcII from Bacillus cereus that mimic the ligands present in other members of this superfamily. We have characterized spectroscopically and modeled the structure of the redesigned sites, which differ substantially from the wild-type enzyme. Despite the changes introduced in the active site, the mutant enzymes retain almost full activity. These results shed some light on the possible evolutionary origin of these metalloenzymes.
金属β-内酰胺酶是一类能够水解β-内酰胺抗生素四元环的锌酶，代表了最新一代的β-内酰胺酶。这些酶属于β-内酰胺酶折叠的锌金属水解酶家族。属于该家族的酶具有双金属活性位点，其结构在不同成员之间因金属配体的点突变而有所不同。在这项工作中，我们将新的金属配体嫁接到蜡样芽孢杆菌BcII的金属结合位点，这些配体模拟了该超家族其他成员中存在的配体。我们通过光谱对重新设计的位点进行了表征并对其结构进行了建模，这些位点与野生型酶有很大不同。尽管活性位点发生了变化，但突变酶仍保留了几乎全部活性。这些结果为这些金属酶可能的进化起源提供了一些线索。
