Improved ligand geometries in crystallographic refinement using AFITT in PHENIX.

ABSTRACT: Modern crystal structure refinement programs rely on geometry restraints to overcome the challenge of a low data-to-parameter ratio. While the classical Engh and Huber restraints work well for standard amino-acid residues, the chemical complexity of small-molecule ligands presents a particular challenge. Most current approaches either limit ligand restraints to those that can be readily described in the Crystallographic Information File (CIF) format, thus sacrificing chemical flexibility and energetic accuracy, or they employ protocols that substantially lengthen the refinement time, potentially hindering rapid automated refinement workflows. PHENIX-AFITT refinement uses a full molecular-mechanics force field for user-selected small-molecule ligands during refinement, eliminating the poten

SUBMITTER: Janowski PA 

PROVIDER: S-EPMC5013598 | biostudies-literature | 2016 Sep

REPOSITORIES: biostudies-literature