题  目： Evolution of a Catalytic Mechanism

时  间： 2013年8月12日（星期一）上午9:30-11:30

地  点： 中山大学南校区生物楼东梯205会议室

报告人： Antony Michael Dean教授 (美国明尼苏达大学)

主持人： 吴仲义 教授

摘要：

　　An outstanding question in molecular evolution is the origin of new catalytic chemistries. The evolution of hydroxynitrile lyase, a plant defense enzyme, from a family of esterases represents a change in chemistry. In esterases catalysis begins with nucleophilic attack by a serine hydroxyl on the carbonyl carbon of the ester bond to form an acyl-enzyme intermediate with release of the alcohol. An activated water is then used to hydrolyze the carboxylic acid from the serine. In hydroxyl nitrile lyase the very same serine acts as a base, abstracting the proton from the hydroxyl to form a carbonyl with concomitant release of cyanide. The shift from nucleophyllic attack to acid-base chemistry is achieved by just three amino acid replacements while retaining the essential catalytic machinery. Our results provide fundamental insights into the evolution of biological novelty.