title: Metal-ligand geometry relevant to proteins and in proteins: sodium and potassium.
abstract: In previous papers [Harding (2001), Acta Cryst. D57, 401-411, and references therein] the geometry of metal-ligand interactions was examined for six metals (Ca, Mg, Mn, Fe, Cu, Zn) using the Protein Data Bank and compared with information from accurately determined structures of relevant small-molecule crystals in the Cambridge Structural Database. Here, the environments of Na(+) and K(+) ions found in protein crystal structures are examined in an equivalent way. Target M(+).O distances are proposed and the agreement with observed distances is summarized. The commonest interactions are with water molecules and the next commonest with main-chain carbonyl O atoms.
authors.affiliation: Institute of Cell and Molecular Biology, University of Edinburgh, Michael Swann Building, Edinburgh EH9 3JR, Scotland, UK. marjorie.harding@ed.ac.uk
authors.forename: Marjorie M
authors.initials: MM
authors.lastname: Harding
mesh_terms: D003461:Crystallography; D030562:Databases, Protein; D008024:Ligands; D008968:Molecular Conformation; D011188:Potassium / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D011506:Proteins / Q000737:chemistry* / Q000378:metabolism*; D012964:Sodium / Q000737:chemistry / Q000378:metabolism*; D055672:Static Electricity; D014867:Water / Q000737:chemistry
chemical_list: D008024:Ligands; D011506:Proteins; D014867:Water; D012964:Sodium; D011188:Potassium