Crystallographic structure of a small molecule SIRT1 activator-enzyme complex

Area of Science:

• Biochemistry
• Structural Biology
• Medicinal Chemistry

Background:

• Sirtuin 1 (SIRT1) is a key NAD(+)-dependent deacetylase involved in cellular regulation.
• SIRT1 is a promising therapeutic target for various human diseases.
• Small molecule sirtuin-activating compounds (STACs) are known to activate SIRT1.

Purpose of the Study:

• To design and characterize a minimal engineered human SIRT1 construct (mini-hSIRT1) for structural studies.
• To determine the crystal structure of a mini-hSIRT1-STAC complex.
• To identify the specific binding site and key interactions between STACs and human SIRT1.

Main Methods:

• Protein engineering of a minimal human SIRT1 construct (mini-hSIRT1).
• X-ray crystallography to solve the structure of the mini-hSIRT1-STAC complex.
• Hydrogen-deuterium exchange mass spectrometry (HDX-MS) and site-directed mutagenesis on full-length hSIRT1.

Main Results:

• A mini-hSIRT1 construct retaining catalytic activity and STAC responsiveness was successfully engineered.
• The crystal structure revealed the STAC-binding site located within the N-terminal domain of hSIRT1.
• HDX-MS and mutagenesis confirmed a specific binding interface and identified critical intermolecular interactions.

Conclusions:

• The study establishes a precise STAC-binding site on human SIRT1.
• Understanding the STAC-hSIRT1 interface is crucial for the rational design of novel therapeutic agents.
• This work advances the development of SIRT1-targeting drugs for diverse diseases.