Date of Presentation
5-5-2022 12:00 AM
College
School of Osteopathic Medicine
Poster Abstract
Human sirtuins are a family of nicotinamide adenine dinucleotide (NAD +)-dependent enzymes that are responsible for removing acyl modifications from lysine residues. Sirtuins are involved in the formation and proliferation of cancers and are thought to regulate the progression of neurodegenerative diseases. Although sirtuins can be pharmacologically targeted by small molecules, it is not easy to modulate the substrate selectivity of sirtuins despite the chemical diversity of their substrates. Here, we report substrate-specific effects on sirtuin conformation and oligomerization that regulate enzyme deacylase activity. We used fluorescent acyl peptide probes to study substrate interactions with two sirtuin isoforms: SIRT2 and SIRT6. We observed that some of the fluorescent acyl peptides bind sirtuins and change their conformation, whereas other probes bind sirtuins without causing such structural changes. Our fluorescent probes also revealed that SIRT2 forms a dimer at relevant cellular concentrations (~100 nM) in contrast to SIRT6, which is exclusively monomeric. SIRT2 undergoes a conformational transition from dimer to monomer when bound to myristoyl-substrate which slows its demyristoylase reaction, but SIRT2 remains dimeric when performing its deacetylase reaction. Our fluorescent peptide probes will continue to be used to examine substrate specific effects on sirtuin structure and function in order to understand how to pharmacologically modulate sirtuin substrate selectivity.
Keywords
Sirtuin 2, Lysine, Neurodegenerative Diseases, NAD, Peptides, Neoplasms, Protein Isoforms
Disciplines
Genetic Processes | Genetic Structures | Medical Molecular Biology | Medicine and Health Sciences | Neoplasms | Nervous System Diseases
Document Type
Poster
Included in
Genetic Processes Commons, Genetic Structures Commons, Medical Molecular Biology Commons, Neoplasms Commons, Nervous System Diseases Commons
Substrate-specific Effect on Sirtuin Conformation and Oligomerization
Human sirtuins are a family of nicotinamide adenine dinucleotide (NAD +)-dependent enzymes that are responsible for removing acyl modifications from lysine residues. Sirtuins are involved in the formation and proliferation of cancers and are thought to regulate the progression of neurodegenerative diseases. Although sirtuins can be pharmacologically targeted by small molecules, it is not easy to modulate the substrate selectivity of sirtuins despite the chemical diversity of their substrates. Here, we report substrate-specific effects on sirtuin conformation and oligomerization that regulate enzyme deacylase activity. We used fluorescent acyl peptide probes to study substrate interactions with two sirtuin isoforms: SIRT2 and SIRT6. We observed that some of the fluorescent acyl peptides bind sirtuins and change their conformation, whereas other probes bind sirtuins without causing such structural changes. Our fluorescent probes also revealed that SIRT2 forms a dimer at relevant cellular concentrations (~100 nM) in contrast to SIRT6, which is exclusively monomeric. SIRT2 undergoes a conformational transition from dimer to monomer when bound to myristoyl-substrate which slows its demyristoylase reaction, but SIRT2 remains dimeric when performing its deacetylase reaction. Our fluorescent peptide probes will continue to be used to examine substrate specific effects on sirtuin structure and function in order to understand how to pharmacologically modulate sirtuin substrate selectivity.