作者:Yana Cen、Jessica N. Falco、Ping Xu、Dou Yeon Youn、Anthony A. Sauve
DOI:10.1039/c0ob00774a
日期:——
The ability to probe for catalytic activities of enzymes and to detect their abundance in complex biochemical contexts has traditionally relied on a combination of kinetic assays and techniques such as western blots that use expensive reagents such as antibodies. The ability to simultaneously detect activity and isolate a protein catalyst from a mixture is even more difficult and currently impossible in most cases. In this manuscript we describe a chemical approach that achieves this goal for a unique family of enzymes called sirtuins using novel chemical tools, enabling rapid detection of activity and isolation of these protein catalysts. Sirtuin deacetylases are implicated in the regulation of many physiological functions including energy metabolism, DNA-damage response, and cellular stress resistance. We synthesized an aminooxy-derivatized NAD+ and a pan-sirtuin inhibitor that reacts on sirtuin active sites to form a chemically stable complex that can subsequently be crosslinked to an aldehyde-substituted biotin. Subsequent retrieval of the biotinylated sirtuin complexes on streptavidin beads followed by gel electrophoresis enabled simultaneous detection of active sirtuins, isolation and molecular weight determination. We show that these tools are cross reactive against a variety of human sirtuin isoforms including SIRT1, SIRT2, SIRT3, SIRT5, SIRT6 and can react with microbial derived sirtuins as well. Finally, we demonstrate the ability to simultaneously detect multiple sirtuin isoforms in reaction mixtures with this methodology, establishing proof of concept tools for chemical studies of sirtuins in complex biological samples.
探测酶的催化活性以及在复杂生化环境中检测其丰度的能力,传统上依赖于动力学测定和诸如使用昂贵试剂(如抗体)的西方印迹等技术。能够同时检测活性并从混合物中分离蛋白催化剂更为困难,在大多数情况下几乎不可能。在本手稿中,我们描述了一种化学方法,利用新型化学工具实现这一目标,针对一种独特的酶家族——去乙酰化酶(sirtuins),从而使得能够快速检测其活性并分离这些蛋白催化剂。去乙酰化酶与许多生理功能的调节相关,包括能量代谢、DNA损伤应答和细胞应激抵抗。我们合成了一种氨氧基衍生的NAD+和一种泛去乙酰化酶抑制剂,该抑制剂会在去乙酰化酶的活性位点反应,形成一种化学稳定的复合物,随后可以与醛基取代的生物素交联。通过链霉亲和素珠子回收生物素化的去乙酰化酶复合物,再通过胶体电泳,我们实现了对活性去乙酰化酶的同时检测、分离和分子量测定。我们展示了这些工具能与多种人类去乙酰化酶亚型(包括SIRT1、SIRT2、SIRT3、SIRT5、SIRT6)交叉反应,并且也能与微生物来源的去乙酰化酶反应。最后,我们展示了能够在反应混合物中同时检测多个去乙酰化酶亚型,确立了在复杂生物样品中进行去乙酰化酶化学研究的概念验证工具。