Investigating the Biological Role of O-Acyl ADP Ribose

Sirtuins;O-acyl ADP ribose;Biophysics

Blazosky, Elyse MWolberger, Cynthia ;

Johns Hopkins University

关键词: Sirtuins;    O-acyl ADP ribose;    Biophysics;   

Others  :  https://jscholarship.library.jhu.edu/bitstream/handle/1774.2/60165/BLAZOSKY-THESIS-2018.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: JOHNS HOPKINS DSpace Repository

【 摘 要 】

Sirtuins are an ancient family of deacetylase enzymes found in all three domains of life, where they have diverse biological roles. These widely studied enzymes are popular drug targets for treating diseases associated with aging, neurological disorders, cardiovascular disorders, metabolic disorders and even cancer.Unlike most deacetylase enzymes which use water to hydrolyze the amide bond linking the acetyl group to a lysine side chain, sirtuins catalyze a unique NAD+-dependent reaction that yields O-acetyl ADP ribose, nicotinamide and the deacetylate lysine.This seemingly wasteful use of NAD+ has led some to hypothesize that sirtuin activity is coupled to NAD+ levels in the cell. While sirtuin activity does rely on NAD+ biosynthesis and salvage pathways, it is unclear whether NAD+ levels fluctuate to a level that could affect sirtuin activity in-vivo. More recent studies have revealed new roles for sirtuins which suggests a more complex role of the sirtuin and a re-evaluation of the current hypothesis for why sirtuins uses NAD+. It has been shown that some sirtuins preferentially remove a variety of acyl lysine groups such as malonyl, succinyl, and butyryl, forming the corresponding O-acyl ADP ribose product. Mass spectrometry studies have revealed an abundance of these acyl modifications on cellular proteins, some of which are thought to result from non-enzymatic reaction with metabolites such as acyl-CoAs. I hypothesize that sirtuins use NAD+ to generate a carrier molecule (ADP ribose) to shuttle the leaving acyl chain to downstream metabolic pathways. This thesis focuses on progress made testing this hypothesis including the synthesis, purification and stability of 13C-labeled O-succinyl ADP ribose, as well as preliminary mass spectrometry metabolomics studies.