Development of computational methods for structure determination of biological macromolecules by X-ray diffraction

 

TITLE

Development of computational methods for structure determination of biological macromolecules by X-ray diffraction

STAFF

Giovanni Luca Cascarano
Annamaria Mazzone
Benedetta Carrozzini
Rocco Caliandro
Dritan Siliqi
Carmelo Giacovazzo*
[*] Personale associato

CNR MODULE

Commessa PM.P07.011: Development and application of computational methods for biomolecule structure determination
Modulo I: Development and application of computational methods for structure determination by X-ray diffraction

KEYWORDS

Crystallographic methods, protein structure, X-ray diffraction

COLLABORATIONS
M.C. Burla and G. Polidori, University of Perugia, Italy
DESCRIPTION

Activities of theorization and implementation of crystallographic methods to solve the phase problem for biological macromolecules are carried out. Procedures for crystal structure determination by ab initio methods, Molecular Replacement techniques, SAD-MAD, SIR-MIR, SIRAS-MIRAS techniques have been developed and implemented in a computer package called Il MILIONE. It is currently distributed from the wwwba.ic.cnr.it.
The following procedures are currently being developed:
-- model completion and refinement by DEA. It combines Electron Density Modification (EDM) and Difference Electron Density Modification (DEDM) techniques with Automatic Model Building (AMB) procedures.
-- phase extension and refinement by Freelunch. Extrapolated modulus and phase values are assigned to non-measured reflections, to cope with finite experimental data resolution limitations.
-- improved Molecular Replacement strategies, to push forward the actual limit of the technique regarding the size and difference of the structural model used with respect to the target structure.

il milione jpg

Graphic window of IL MILIONE package.

 

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

Crystal structure of the largest protein solved by crystallographic ab initio methods (PDB code 1E8U). Secondary structure elements are reported in colors: red for α-elices, yellow for β-sheet, green for loops.

 

CONTACTS

 

Giovanni Luca Cascarano
Email : gianluca.cascaranoATic.cnr.it
Tel : +39/080/5929145

 

Last Updated (Tuesday, 07 December 2010 10:42)