A fast selenium derivatization strategy for crystallization and phasing of RNA structures

Area of Science:

• Structural Biology
• Biochemistry
• Crystallography

Background:

• The phase problem remains a significant challenge in RNA crystallography.
• Site-specific RNA labeling is crucial for solving the phase problem.
• 2 -methylseleno (2 -SeCH3) RNA is a promising labeling strategy.

Purpose of the Study:

• To develop an efficient strategy for RNA and RNA/protein complex crystallization and structure determination.
• To leverage 2 -SeCH3 RNA labeling for improved crystallographic phasing.
• To assess the utility of 2 -SeCH3 RNA in overcoming crystallographic challenges.

Main Methods:

• Developed a strategy involving preliminary crystallization screening of 2 -OCH(3)-modified RNA sequences.
• Replaced 2 -OCH(3) groups with 2 -SeCH3 counterparts for labeling.
• Validated the method on two test cases for RNA and RNA/protein complex structure determination.

Main Results:

• Successfully determined the crystal structures of RNA and RNA/protein complexes using the developed method.
• Demonstrated that 2 -SeCH3-modified RNA exhibits increased resistance to X-ray radiolysis compared to 5-halogen-modified RNA.
• Obtained high-quality experimental electron density maps due to enhanced radiation resistance.

Conclusions:

• The developed strategy provides an efficient approach for RNA and RNA/protein complex crystallization and structure determination.
• 2 -SeCH3 RNA labeling is effective in tackling the phase problem in RNA crystallography.
• The enhanced X-ray resistance of 2 -SeCH3 RNA facilitates the collection of superior quality crystallographic data.