PT - JOURNAL ARTICLE AU - Xiangying Guan AU - Alok Upadhyay AU - Raj Chakrabarti TI - Mechanism-based sirtuin enzyme activation AID - 10.1101/027243 DP - 2015 Jan 01 TA - bioRxiv PG - 027243 4099 - http://biorxiv.org/content/early/2015/09/28/027243.short 4100 - http://biorxiv.org/content/early/2015/09/28/027243.full AB - Sirtuin enzymes are NAD+-dependent protein deacylases that play a central role in the regulation of healthspan and lifespan in organisms ranging from yeast to mammals. There is intense interest in the activation of the seven mammalian sirtuins (SIRT1-7) in order to extend mammalian healthspan and lifespan. However, there is currently no understanding of how to design sirtuin-activating compounds beyond allosteric activators of SIRT1-catalyzed reactions that are limited to particular substrates. Moreover, across all families of enzymes, only a dozen or so distinct classes of non-natural small molecule activators have been characterized, with only four known modes of activation among them. None of these modes of activation are based on the unique catalytic reaction mechanisms of the target enzymes. Here, we report a general mode of sirtuin activation that is distinct from any of the known modes of enzyme activation. Based on the conserved mechanism of sirtuin-catalyzed deacylation reactions, we establish biophysical properties of small molecule modulators that can result in enzyme activation for any sirtuin and any substrate. Building upon this framework, we propose mechanism-based workflows for the design of new sirtuin-activating compounds. We demonstrate experimentally the existence of small molecule modulators that activate multiple sirtuins through the proposed mode of action.Significance Statement Compared to enzyme inhibitors, which constitute the vast majority of today's drugs, enzyme activators have considerable advantages. However, they are much more difficult to design, because enzymatic catalysis has been optimized over billions of years of evolution. Sirtuin-activating compounds (STACs) are enzyme activators that can extend mammalian healthspan and lifespan. Unfortunately, the only known mode of STAC action is limited to accelerating selected functions of a single mammalian sirtuin enzyme. Here, we report a wholly new mode of enzyme activation that exploits the common catalytic mechanism of all sirtuin enzymes, hence being applicable to any function of any sirtuin. This discovery expands our understanding of enzyme activation, and lays the foundation for development of a new generation of drugs for mammalian healthspan and lifespan extension.