Assessment of electron irradiation damage to biomolecules using the Patterson function

Area of Science:

• Materials Science
• Crystallography
• Radiation Chemistry

Background:

• Electron radiation is a common tool in materials analysis.
• Understanding radiation damage is crucial for preserving sample integrity.
• 5-iodouracil is a biologically relevant molecule susceptible to radiation effects.

Purpose of the Study:

• To develop and describe a method for assessing electron radiation damage in 5-iodouracil.
• To correlate observed changes in Patterson maps with specific types of radiation damage.
• To quantify radiation damage using a disorder parameter.

Main Methods:

• Utilizing the Patterson function to analyze electron diffraction patterns.
• Recording diffraction data at incrementally increasing electron irradiation doses.
• Computing and comparing Patterson maps to track structural and chemical alterations.

Main Results:

• Patterson maps showed distinct changes correlating with increasing electron irradiation.
• These changes were attributed to both structural and chemical damage to the 5-iodouracil.
• A disorder parameter was identified and shown to increase proportionally with irradiation dose.

Conclusions:

• The Patterson function method effectively assesses electron radiation damage in 5-iodouracil.
• Radiation damage manifests as measurable changes in Patterson maps and an increasing disorder parameter.
• This methodology provides a quantitative approach to studying radiation-induced structural and chemical modifications.