Visualizing transiently associated catalytic domains in assembly-line biosynthesis using cryo-electron microscopy.

Area of Science:

• Structural Biology
• Biochemistry
• Molecular Biology

Background:

• Cryo-electron microscopy (cryo-EM) excels at determining structures of large protein complexes.
• However, conformational flexibility and heterogeneity in transient complexes pose challenges for cryo-EM.
• Understanding these dynamic interactions is vital for elucidating biological functions.

Purpose of the Study:

• To demonstrate successful visualization of transient protein-protein interactions using cryo-EM.
• To highlight methods for studying dynamic complexes in assembly-line biosynthesis.
• To enable structure-function relationship studies of fleeting molecular assemblies.

Main Methods:

• Application of chemical crosslinking to stabilize transient protein complexes.
• Utilizing partial signal subtraction for data analysis.
• Employing localized reconstruction techniques for dynamic systems.
• Cryo-electron microscopy (cryo-EM) for structural determination.

Main Results:

• Successful cryo-EM visualization of transient protein interactions in fatty acid, polyketide, and terpene biosynthesis.
• Demonstrated efficacy of chemical crosslinking in stabilizing dynamic complexes for structural analysis.
• Extracted valuable structural information from inherently dynamic systems using advanced cryo-EM data processing.

Conclusions:

• Specialized cryo-EM approaches, including chemical crosslinking and advanced image processing, can overcome challenges posed by transient protein complexes.
• These methods allow direct experimental observation of dynamic complexes in assembly-line biosynthesis.
• Enables crucial structure-function insights into previously intractable molecular interactions.