PROTAC-induced Protein Structural Dynamics in Targeted Protein Degradation

Area of Science:

• Biochemistry
• Molecular Biology
• Drug Discovery

Background:

• PROteolysis TArgeting Chimeras (PROTACs) harness the ubiquitin-proteasome system for targeted protein degradation.
• Ternary complex formation between PROTAC, target protein, and E3 ligase is essential but doesn't guarantee degradation.
• PROTAC-induced complex dynamics critically influence ubiquitination and degradation outcomes.

Purpose of the Study:

• To computationally investigate how varying PROTAC linkers affect the degradation potency of PROTACs targeting bromodomain-containing protein 4 (BRD4 ^BD1).
• To elucidate the structural dynamics underlying differential protein degradation mediated by PROTACs with identical warheads but distinct linkers.

Main Methods:

• Computational modeling of PROTAC-induced ternary complexes with Cereblon (CRBN) and Culling-Ring Ligase 4A (CRL4A) E3 ligases.
• Atomistic molecular dynamics simulations to analyze protein complex dynamics and interactions.
• Investigation of PROTAC-dependent dynamics facilitating lysine residue presentation for ubiquitination.

Main Results:

• PROTAC linkers significantly impact residue-interaction networks and essential motions of the degradation machinery.
• Linker variations alter the dynamics, influencing the arrangement of target protein lysine residues for ubiquitination.
• Identical PROTAC warheads exhibited varying degradation potencies, directly correlated with linker-modulated complex dynamics.

Conclusions:

• PROTAC linker design is critical for modulating protein dynamics and optimizing targeted protein degradation.
• Structural dynamics provide a key perspective for understanding and improving PROTAC efficacy.
• Insights guide future PROTAC design for enhanced therapeutic potential.