Structural and Functional Analysis of Human SIRT1

Abstract

SIRT1 is a NAD+-dependent deacetylase that plays important roles in many cellular processes. SIRT1 activity is uniquely controlled by a C-terminal regulatory segment (CTR). Here we present crystal structures of the catalytic domain of human SIRT1 in complex with the CTR in an open apo form and a closed conformation in complex with a cofactor and a pseudo-substrate peptide. The catalytic domain adopts the canonical sirtuin fold. The CTR forms a β hairpin structure that complements the β sheet of the NAD+-binding domain, covering an essentially invariant, hydrophobic surface. The apo form adopts a distinct open conformation, in which the smaller subdomain of SIRT1 undergoes a rotation with respect to the larger NAD+-binding subdomain. A biochemical analysis identifies key residues in the active site, an inhibitory role for the CTR, and distinct structural features of the CTR that mediate binding and inhibition of the SIRT1 catalytic domain.

Sirtuin 5: a review of structure, known inhibitors and clues for developing new inhibitors

“…The loop N, which connects the helix α3 of the zinc 2+ binding domain and the α2 helix of the Rossmann fold domain, is important for NAD + binding (Figure 2). By comparing crystal structures of SIRT5 with other sirtuins including SIRT1 (Davenport et al, 2014), SIRT2 (Moniot et al, 2013), SIRT3 (Jin et al, 2009), and SIRT6 , SIRT5 was observed to have a similar overall domain organization and fold to the structures of SIRT1, SIRT2, and SIRT3 ( Figure 3A), but a different domain fold with SIRT6 especially in zinc 2+ binding domain and catalytic site ( Figure 3B). As shown in Figure 3A, the catalytic sites of SIRT5, SIRT1, SIRT2, and SIRT3 superimpose very closely, and the residues around the catalytic site are relatively conserved.…”

Structural basis for allosteric, substrate-dependent stimulation of SIRT1 activity by resveratrol

“…Crystal structures of several archael, yeast, and human sirtuins have been solved, and they revealed a conserved catalytic core composed of a Rossmann-fold large lobe and a zinc-containing small lobe (Finnin et al 2001;Min et al 2001;Avalos et al 2002;Zhao et al 2003Zhao et al , 2013Schuetz et al 2007;Jin et al 2009;Pan et al 2011;Davenport et al 2014). NAD is bound in the cleft formed between the two lobes, with the nicotinamide group pointing inside of the cleft.…”

“…The structure of the CD of SIRT1 with and without the C-terminal ESA polypeptide has been determined previously (Zhao et al 2013;Davenport et al 2014). The structure of the catalytic core resembles that of other sirtuins, and the ESA polypeptide folds into a β hairpin, which is juxtaposed with the parallel β strands of the Rossmann-fold domain and forms an extended, mixed β sheet (Davenport et al 2014).…”

Identification of Bichalcones as Sirtuin Inhibitors by Virtual Screening and <em>in Vitro </em>Testing

“…antibacterial, antiviral, anticancer, anti-inflammatory and properties [10], this collection represents a good starting point to search for novel inhibitors or modulators of sirtuins. Sirtuins share a highly conserved catalytic core composed of two subdomains; a large NAD + binding domain (Rossmann fold) and a smaller domain generated by two insertions in the NAD + binding domain, together with a helical module and a zinc-binding module [29,30].…”