High-Resolution Cryo-EM Analyses of Nucleosomes.

Area of Science:

• Structural Biology
• Molecular Biology
• Biochemistry

Background:

• The nucleosome, composed of DNA and a histone octamer, is the fundamental unit of chromatin.
• X-ray crystallography has provided nucleosome structures, but crystal packing may limit revealing their full versatility.
• Cryo-electron microscopy (cryo-EM) single-particle analysis enables visualization of diverse nucleosome structures and complexes.

Purpose of the Study:

• To present a high-resolution cryo-EM method for nucleosome structural analysis.
• To detail procedures for nucleosome purification, cryo-EM grid preparation, data collection, and processing.
• To provide a starting point for cryo-EM studies on nucleosomes and their protein complexes.

Main Methods:

• High-resolution cryo-electron microscopy (cryo-EM) single-particle analysis.
• Detailed protocols for nucleosome purification.
• Established procedures for cryo-EM grid preparation, data collection, and data processing.

Main Results:

• A robust method for high-resolution structural analysis of nucleosomes using cryo-EM.
• Demonstration of cryo-EM's capability to reveal structural diversity beyond crystal packing limitations.
• A comprehensive guide for implementing cryo-EM for nucleosome research.

Conclusions:

• The presented cryo-EM method offers a powerful approach for detailed nucleosome structural studies.
• This technique overcomes limitations of previous methods, enabling visualization of nucleosome structural versatility.
• The method serves as a valuable resource for future cryo-EM investigations of nucleosomes and associated proteins.