Neutron protein crystallography: A complementary tool for locating hydrogens in proteins

Area of Science:

• Structural biology
• Biophysics
• Crystallography

Background:

• Neutron protein crystallography directly visualizes hydrogen and deuterium positions.
• Neutrons interact strongly with atomic nuclei, enabling precise localization.
• This method avoids radiation damage, allowing repeated measurements on the same crystal.

Purpose of the Study:

• To review the fundamental principles of neutron protein crystallography.
• To present the scientific information obtainable from neutron structures.
• To discuss practical aspects of implementing this technique.

Main Methods:

• Utilizing neutron diffraction on protein crystals.
• Employing isotopic substitution to enhance neutron scattering.
• Collecting data using specialized instruments and processing with specific software.

Main Results:

• Demonstration of unambiguous hydrogen atom positioning at typical resolutions.
• Capability for parametric studies due to minimal radiation damage.
• Successful joint X-ray/neutron structure refinement strategies.

Conclusions:

• Neutron protein crystallography provides unique, invaluable data for understanding protein chemistry.
• The review balances the technique's potential with practical considerations for its application.
• Examples highlight the significant scientific contributions of neutron structural data.