title: The solvent component of macromolecular crystals.
abstract: The mother liquor from which a biomolecular crystal is grown will contain water, buffer molecules, native ligands and cofactors, crystallization precipitants and additives, various metal ions, and often small-molecule ligands or inhibitors. On average, about half the volume of a biomolecular crystal consists of this mother liquor, whose components form the disordered bulk solvent. Its scattering contributions can be exploited in initial phasing and must be included in crystal structure refinement as a bulk-solvent model. Concomitantly, distinct electron density originating from ordered solvent components must be correctly identified and represented as part of the atomic crystal structure model. Herein, are reviewed (i) probabilistic bulk-solvent content estimates, (ii) the use of bulk-solvent density modification in phase improvement, (iii) bulk-solvent models and refinement of bulk-solvent contributions and (iv) modelling and validation of ordered solvent constituents. A brief summary is provided of current tools for bulk-solvent analysis and refinement, as well as of modelling, refinement and analysis of ordered solvent components, including small-molecule ligands.
authors.affiliation: Center for Biomedicine, European Academy of Bozen/Bolzano (EURAC), Viale Druso 1, Bozen/Bolzano, I-39100 Südtirol/Alto Adige, Italy.
authors.forename: Christian X
authors.initials: CX
authors.lastname: Weichenberger
authors.affiliation: Physical Biosciences Division, Lawrence Berkeley National Laboratory (LBNL), 1 Cyclotron Road, Mail Stop 64R0121, Berkeley, CA 94720, USA.
authors.forename: Pavel V
authors.initials: PV
authors.lastname: Afonine
authors.affiliation: College of Science and Mathematics, California State University, San Marcos, CA 92078, USA.
authors.forename: Katherine
authors.initials: K
authors.lastname: Kantardjieff
authors.affiliation: Department of Forensic Crystallography, k.-k. Hofkristallamt, 991 Audrey Place, Vista, CA 92084, USA.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Rupp
mesh_terms: D003460:Crystallization; D018360:Crystallography, X-Ray; D046911:Macromolecular Substances / Q000737:chemistry*; D008958:Models, Molecular; D012997:Solvents / Q000737:chemistry*
chemical_list: D046911:Macromolecular Substances; D012997:Solvents
keywords: bulk solvent; macromolecular crystals; ordered solvent; solvent content