Development of computational methods for structure determination of biological macromolecules by neutron diffraction

 

TITLE

Development of computational methods for structure determination of biological macromolecules by neutron diffraction

STAFF

Dritan Siliqi
Rocco Caliandro


KEYWORDS

Crystallographic methods, protein structure, neutron diffraction

COLLABORATIONS

Dr. P. Langan and Dr. M. Mustyakimov from the Protein Crystallography Station at Los Alamos National Laboratory (Los Alamos, NM, USA)


DESCRIPTION

New computational tools are developed and implemented for neutron diffraction data analysis. The procedures aims at determining the hydrogen and deuterium positions in protein structures. The following procedures are currently being developed:
-- n-FreeLunch, based on extrapolation of modulus and phase values from measured to non-measured reflections behind and beyond the experimental resolution limit.
-- NDM-DNDM, based on cycles where the neutron density map and the difference neutron density map are modified.
The procedures are applied to the highest positive part of map to find deuterium positions and its lowest negative part to find hydrogen positions.
Procedures for model completion and refinement by using both X-ray and neutron data are being developed in the framework of IL MILIONE and PHENIX software packages.

 

Development of computational methods for structure determination of biological macromolecules by neutron diffraction - Img

Protein with PDB code 2MB5 - Negative neutron density map before (blue) and after (green) n-FreeLunch, superposed to the published coordinates of the Lys47 residue.

CONTACTS


Dritan Siliqi
Email: dritan.siliqiATic.cnr.it
Tel.: +390805929164

 

Last Updated (Tuesday, 21 December 2010 16:03)