Ensemble structure description of Lys63-linked diubiquitin

Area of Science:

• Biochemistry
• Structural Biology
• Cell Signaling

Background:

• Ubiquitin chains are critical signaling molecules in cells.
• Lysine-63 (K63)-linked ubiquitin chains play roles in various cellular processes, including DNA repair and signal transduction.
• Understanding the structural dynamics of K63-linked ubiquitin is essential for deciphering its signaling mechanisms.

Purpose of the Study:

• To present the ensemble structure coordinates for Lysine-63-linked diubiquitin (K63-diUb).
• To provide experimental details for characterizing the conformational states and dynamics of K63-diUb.
• To offer a framework for studying other multi-domain proteins.

Main Methods:

• Determination of the ensemble structure of K63-diUb using atomic coordinates (PDB ID: 2N2K).
• Application of intramolecular paramagnetic restraints to capture protein dynamics.
• Analysis of conformational states and their relative occupancies.

Main Results:

• K63-diUb exists in three distinct conformational states.
• Each conformation exhibits different subunit orientations, enabling specific target protein recognition.
• The ensemble structure recapitulates protein dynamics through multiple atomic locations.

Conclusions:

• The conformational plasticity of K63-diUb is key to its function in specific target recognition and signal encoding.
• The presented experimental methods can be applied to study the structure and dynamics of other multi-domain proteins.
• This work provides insights into the molecular mechanisms underlying K63 ubiquitin signaling.