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On the application of an experimental multipolar pseudo-atom library for accurate refinement of small-molecule and protein crystal structures
Static deformation of the electron density for a phenyl group C6H5−CH2– after library transfer. Blue and red surfaces denote positive +0.4 e Å–3 and negative –0.1 e Å–3 density levels respectively.
Acta Cryst. (2007). A63, 108–125 [doi:10.1107/S0108767306053748]A library describing the precise electron density of all chemical groups present in proteins has been developed. The deformation electron density of atoms is described in terms of multipolar functions. The library is obtained from the crystallographic analysis of several peptide crystals at ultra-high resolution. Library transfer to a crystal structure at atomic resolution results in improved crystallographic indices and electrostatic potential.
B. Zarychta, V. Pichon-Pesme, B. Guillot, C. Lecomte and C. Jelsch