Catalytic promiscuity in a protein superfamily

尽管在基础和应用研究方面进行了大量的研究工作，但对酶催化的理解仍然是一个艰巨的挑战。我们的理解当然没有通过最严格的测试--即制造符合天然酶效率的催化剂。这个建议解决了水解酶的催化效率的决定因素，作为一个测试床的催化剂的超家族，连接的碱性磷酸酶超家族的成员，以及经常相互和相互催化混杂的结构同源性。从我们最近鉴定的一个显著的例子多滥交和高效率（Proc.Natl. Acad. Sci - in Press，doi/10.1073/pnas.0903951107），我们提出通过结构和动力学分析以及通过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.