title: Cation-pi interactions in structural biology.
abstract: Cation-pi interactions in protein structures are identified and evaluated by using an energy-based criterion for selecting significant sidechain pairs. Cation-pi interactions are found to be common among structures in the Protein Data Bank, and it is clearly demonstrated that, when a cationic sidechain (Lys or Arg) is near an aromatic sidechain (Phe, Tyr, or Trp), the geometry is biased toward one that would experience a favorable cation-pi interaction. The sidechain of Arg is more likely than that of Lys to be in a cation-pi interaction. Among the aromatics, a strong bias toward Trp is clear, such that over one-fourth of all tryptophans in the data bank experience an energetically significant cation-pi interaction.
authors.affiliation: Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
authors.forename: J P
authors.initials: JP
authors.lastname: Gallivan
authors.forename: D A
authors.initials: DA
authors.lastname: Dougherty
mesh_terms: D001120:Arginine; D002412:Cations / Q000737:chemistry*; D006639:Histidine; D008239:Lysine; D008956:Models, Chemical; D008958:Models, Molecular; D010649:Phenylalanine; D011487:Protein Conformation; D011506:Proteins / Q000737:chemistry*; D014364:Tryptophan; D014443:Tyrosine
chemical_list: D002412:Cations; D011506:Proteins; D014443:Tyrosine; D010649:Phenylalanine; D006639:Histidine; D014364:Tryptophan; D001120:Arginine; D008239:Lysine