Department of Chemistry, The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA.
J Am Chem Soc. 2009 Dec 30;131(51):18206-7. doi: 10.1021/ja907271a.
An enamine intermediate is believed to be the central feature of biological catalysts, such as aldolases and small molecule amine organocatalysts. Despite decades of investigation of naturally occurring aldolase enzymes and recent studies on designed aldolase antibodies and organocatalysts, direct structural observation of an enamine intermediate has proven to be rare. Herein, we report the observation of a stable enamine intermediate in the crystal structure of an aldolase antibody 33F12 in complex with a 1,3-diketone derivative. This enamine complex structure provides strong evidence that fewer residues are essential for amine catalysis within the hydrophobic environments of this catalytic antibody than speculated for natural aldolase enzymes and should serve to guide future studies aimed at the rational design of these types of catalysts, as well as organocatalysts. Indeed, enamine catalysis in proteins might be more simplistic than previously imagined.
烯胺中间体被认为是生物催化剂（如醛缩酶和小分子胺有机催化剂）的核心特征。尽管对天然存在的醛缩酶酶进行了数十年的研究，以及最近对设计的醛缩酶抗体和有机催化剂进行了研究，但烯胺中间物的直接结构观察仍然很少见。在此，我们报告了在与 1,3-二酮衍生物结合的醛缩酶抗体 33F12 的晶体结构中观察到稳定的烯胺中间体。该烯胺复合物结构为在这种催化抗体的疏水环境中，胺催化所需的残基数比天然醛缩酶酶推测的要少提供了强有力的证据，并且应该有助于指导旨在合理设计此类催化剂以及有机催化剂的未来研究。实际上，蛋白质中的烯胺催化可能比以前想象的要简单。
