Structural Insights Into centSIRT6: Bioinformatic Analysis of N308K and A313S Substitution Effects

Sirtuin 6 (SIRT6), a member of the class III histone deacetylase (HDAC) family, is crucial for the maintenance of general health and is associated with increased life expectancy and resistance to age-related diseases such as cancer and metabolic disorders. A comparative analysis of the SIRT6 gene in Ashkenazi Jewish (AJ) centenarians and noncentenarian controls found a distinct allele, centSIRT6, enriched in the centenarian group. This allele features 2 linked substitutions, N308K and A313S, and exhibits enhanced functions, including more efficient suppression of LINE1 retrotransposons, improved repair of DNA double-strand breaks, and increased efficiency in cancer cell killing. Notably, centSIRT6 shows lower deacetylase activity but higher mono-adenosine diphosphate (ADP) ribosyl transferase activity compared with the wild-type enzyme. This study used several bioinformatics tools to explore the structural changes caused by the N308K and A313S substitutions in centSIRT6 and to elucidate how these alterations contribute to changes in the enzymatic activities of SIRT6. The results indicate that these mutations reduce the structural flexibility of centSIRT6, thus weakening its interactions with acetyl-lysine but strengthening its interactions with ADP-ribose. This research provides useful information for future experimental studies to further investigate the molecular mechanisms of centSIRT6.