New computational tools for H/D determination in macromolecular structures from neutron data.
Two new computational methods dedicated to neutron crystallography, called n-FreeLunch and DNDM-NDM, have been developed and successfully tested. The aim in developing these methods is to determine hydrogen and deuterium positions in macromolecular structures by using information from neutron density maps. Of particular interest is resolving cases in which the geometrically predicted hydrogen or deuterium positions are ambiguous. The methods are an evolution of approaches that are already applied in X-ray crystallography: extrapolation beyond the observed resolution (known as the FreeLunch procedure) and a difference electron-density modification (DEDM) technique combined with the electron-density modification (EDM) tool (known as DEDM-EDM). It is shown that the two methods are complementary to each other and are effective in finding the positions of H and D atoms in neutron density maps.
Institute of Crystallography, CNR, Via G. Amendola 122/O, 70126 Bari, Italy. dritan.siliqi@ic.cnr.it
Dritan
D
Siliqi
Rocco
R
Caliandro
Benedetta
B
Carrozzini
Giovanni Luca
GL
Cascarano
Annamaria
A
Mazzone
D019295:Computational Biology; D003903:Deuterium / Q000032:analysis*; D006859:Hydrogen / Q000032:analysis*; D008958:Models, Molecular; D033363:Neutron Diffraction; D009502:Neutrons; D011506:Proteins / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared
D011506:Proteins; D006859:Hydrogen; D003903:Deuterium