Premium
Cl–π interactions in protein–ligand complexes
Author(s) -
Imai Yumi N.,
Inoue Yoshihisa,
Nakanishi Isao,
Kitaura Kazuo
Publication year - 2008
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1110/ps.033910.107
Subject(s) - ring (chemistry) , chemistry , crystallography , ligand (biochemistry) , pi interaction , atom (system on chip) , ab initio , interaction energy , benzene , molecule , receptor , biochemistry , organic chemistry , computer science , embedded system
During systematic analysis of nonbonded contacts in protein–ligand complexes derived from crystal structures in the Protein Data Bank, Cl–π interactions have been found, not only in the well‐documented serine proteases but also, to a lesser extent, in other proteins. From geometric analysis of such Cl–π interactions in the crystal structures, two distinct geometries were found: the “edge‐on” approach of a Cl atom to a ring atom or C–C bond and the “face‐on” approach toward the ring centroid with an average interatomic distance of 3.6 Å. High‐level ab initio calculations using benzene–chlorohydrocarbon model systems elucidated that the calculated Cl–π interaction energy is −2.01 kcal/mol, and the dispersion force is the major source of attraction. We also discussed the geometric flexibility in Cl–π interactions and a relationship between the intensity of the π density in an aromatic ring and the interaction position of the Cl atom.