Human SIRT1 Multispecificity Is Modulated by Active-Site Vicinity Substitutions during Natural Evolution |
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| Authors: | Adi Hendler Eyal Akiva Mahakaran Sandhu Dana Goldberg Eyal Arbely Colin J Jackson Amir Aharoni |
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| Affiliation: | 1. Department of Life Sciences, Ben-Gurion University of the Negev, Be’er Sheva, Israel;2. National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Be’er Sheva, Israel;3. Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA;4. Research School of Chemistry, Australian National University, Acton, ACT, Australia;5. Department of Chemistry, Ben-Gurion University of the Negev, Be’er Sheva, Israel |
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| Abstract: | Many enzymes that catalyze protein post-translational modifications can specifically modify multiple target proteins. However, little is known regarding the molecular basis and evolution of multispecificity in these enzymes. Here, we used a combined bioinformatics and experimental approaches to investigate the evolution of multispecificity in the sirtuin-1 (SIRT1) deacetylase. Guided by bioinformatics analysis of SIRT1 orthologs and substrates, we identified and examined important amino acid substitutions that have occurred during the evolution of sirtuins in Metazoa and Fungi. We found that mutation of human SIRT1 at these positions, based on sirtuin orthologs from Fungi, could alter its substrate specificity. These substitutions lead to reduced activity toward K382 acetylated p53 protein, which is only present in Metazoa, without affecting the high activity toward the conserved histone substrates. Results from ancestral sequence reconstruction are consistent with a model in which ancestral sirtuin proteins exhibited multispecificity, suggesting that the multispecificity of some metazoan sirtuins, such as hSIRT1, could be a relatively ancient trait. |
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| Keywords: | multispecificity sirtuins deacetylation |
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