title: Calculation of the magnitude and orientation of electrostatic interactions between small aromatic rings in peptides and proteins: implications for angiotensin II.
abstract: Electrostatic interactions between aromatic rings are believed to contribute to the intramolecular structuring and biological function of peptides and proteins. The modes of interaction of benzene with 1) benzene (Phe:Phe), 2) imidazole (Phe:His), and 3) imidazole anion (Phe:His), were calculated using all-electron ab initio wavefunctions. In all cases parallel-plate stackings were found to be purely repulsive, whereas perpendicular-plate geometries were attractive with interaction energies of -0.82 (Phe:Phe), -1.19 (Phe:His) and -3.39 (Phe:His) kcal/mole. These data show that small ring interactions in peptides and proteins will prefer perpendicular-plate geometry. For the proposed His:Phe interaction in angiotensin II, the attraction will be three times greater when the imidazole ring carries a negative charge.
authors.affiliation: Department of Chemistry, University of Exeter, U.K.
authors.forename: P W
authors.initials: PW
authors.lastname: Fowler
authors.forename: G J
authors.initials: GJ
authors.lastname: Moore
mesh_terms: D000804:Angiotensin II; D001554:Benzene; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D007093:Imidazoles; D011487:Protein Conformation
chemical_list: D007093:Imidazoles; D000804:Angiotensin II; C029899:imidazole; D001554:Benzene