Catalytic promiscuity in a protein superfamily

尽管在基础和应用研究方面付出了巨大的努力，但对酶催化的理解仍然是一项艰巨的挑战。我们的理解肯定没有通过最严格的考验——制造满足天然酶效率的催化剂。该提案解决了水解酶催化效率的决定因素，使用催化剂超家族作为试验台，这些催化剂超家族通过结构同源性作为碱性磷酸酶超家族的成员以及通常相互和交叉的催化混杂而连接。从我们最近发现的一个多重混杂和高效率的显着例子开始（Proc. Natl. Acad. Sci - 出版中，doi/10.1073/pnas.0903951107），我们建议通过结构和动力学分析以及定向进化来解决决定选择性和效率的因素。

Understanding of enzyme catalysis remains a daunting challenge, despite intense research efforts in basic and applied research. Our understanding certainly fails the most severe test - that of making catalysts that meet the efficiency of natural enzymes. This proposal addresses the determinants of catalytic efficiency in hydrolytic enzymes, using as a test bed a superfamily of catalysts that are connected by structural homology as members of the alkaline phosphatase superfamily as well as often reciprocal and crosswise catalytic promiscuity. Starting from our recent identification of one remarkable example for multiple promiscuity and high efficiency (Proc. Natl. Acad. Sci - in press, doi/10.1073/pnas.0903951107), we propose to address the factors that determine selectivity and efficiency, by structural and kinetic analysis and by directed evolution.