RigidFinder: a fast and sensitive method to detect rigid blocks in large macromolecular complexes

Area of Science:

• Structural biology
• Computational biology
• Biophysics

Background:

• Large macromolecular complexes undergo significant conformational changes.
• Analyzing these motions requires identifying rigid blocks across different structures.
• Existing tools struggle with consistent rigid block identification in very large complexes.

Purpose of the Study:

• To introduce RigidFinder, a novel computational method for identifying rigid blocks in macromolecular complexes.
• To enable sensitive analysis of large-scale conformational changes across diverse biological scales.
• To provide a web server for real-time application to large structures.

Main Methods:

• RigidFinder defines rigidity based on conserved inter-residue distances across conformations.
• Utilizes an efficient quasi-dynamic programming search algorithm.
• Capable of identifying blocks from nonconsecutive fragments and multiple polypeptide chains.

Main Results:

• RigidFinder successfully identifies rigid blocks across various scales, from loops to large complexes.
• Demonstrated application to Pyruvate Phosphate Dikinase, T7 RNA polymerase, RNA polymerase II, and GroEL.
• Results show excellent agreement with expert-identified rigid blocks.

Conclusions:

• RigidFinder offers a sensitive and scalable method for analyzing conformational dynamics in macromolecular complexes.
• The approach overcomes limitations of existing tools for large structures.
• The web server facilitates broader application in structural and computational biology.