title: Direct detection of CH/pi interactions in proteins.
abstract: XH/pi interactions make important contributions to biomolecular structure and function. These weakly polar interactions, involving pi-system acceptor groups, are usually identified from the three-dimensional structures of proteins. Here, nuclear magnetic resonance spectroscopy has been used to directly detect methyl/pi (Me/pi) interactions in proteins at atomic resolution. Density functional theory calculations predict the existence of weak scalar (J) couplings between nuclei involved in Me/pi interactions. Using an optimized isotope-labelling strategy, these J couplings have been detected in proteins using nuclear magnetic resonance spectroscopy. The resulting spectra provide direct experimental evidence of Me/pi interactions in proteins and allow a simple and unambiguous assignment of donor and acceptor groups. The use of nuclear magnetic resonance spectroscopy is an elegant way to identify and experimentally characterize Me/pi interactions in proteins without the need for arbitrary geometric descriptions or pre-existing three-dimensional structures.
authors.affiliation: CEA, Institut de Biologie Structurale Jean-Pierre Ebel, Grenoble, France. michael.plevin@ibs.fr
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Plevin
authors.forename: David L
authors.initials: DL
authors.lastname: Bryce
authors.forename: Jérôme
authors.initials: J
authors.lastname: Boisbouvier
mesh_terms: D015295:Antigens, Tumor-Associated, Carbohydrate / Q000737:chemistry* / Q000378:metabolism*; D002244:Carbon / Q000737:chemistry*; D006801:Humans; D006860:Hydrogen Bonding; D008956:Models, Chemical; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular; D011487:Protein Conformation; D025801:Ubiquitin / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D015295:Antigens, Tumor-Associated, Carbohydrate; C472766:Gb3 antigen; D025801:Ubiquitin; D002244:Carbon