title: Strength of the Calpha H..O hydrogen bond of amino acid residues.
abstract: Although the peptide C(alpha)H group has historically not been thought to form hydrogen bonds within proteins, ab initio quantum calculations show it to be a potent proton donor. Its binding energy to a water molecule lies in the range between 1.9 and 2.5 kcal/mol for nonpolar and polar amino acids; the hydrogen bond (H-bond) involving the charged lysine residue is even stronger than a conventional OH..O interaction. The preferred H-bond lengths are quite uniform, about 3.32 A. Formation of each interaction results in a downfield shift of the bridging hydrogen's chemical shift and a blue shift in the C(alpha)H stretching frequency, potential diagnostics of the presence of such an H-bond within a protein.
authors.affiliation: Department of Chemistry and Biochemistry, Utah State University, Logan 84322-0300, USA. scheiner@cc.usu.edu
authors.forename: S
authors.initials: S
authors.lastname: Scheiner
authors.forename: T
authors.initials: T
authors.lastname: Kar
authors.forename: Y
authors.initials: Y
authors.lastname: Gu
mesh_terms: D000596:Amino Acids / Q000737:chemistry* / Q000378:metabolism; D002244:Carbon / Q000737:chemistry* / Q000378:metabolism; D003198:Computer Simulation; D006859:Hydrogen / Q000737:chemistry* / Q000378:metabolism; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D010100:Oxygen / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding; D013816:Thermodynamics
chemical_list: D000596:Amino Acids; D002244:Carbon; D006859:Hydrogen; D010100:Oxygen