title: Analysis of NAD 2D-NMR spectra of saturated fatty acids in polypeptide aligning media by experimental and modeling approaches.
abstract: The overall and detailed elucidation (including the stereochemical aspects) of enzymatic mechanisms requires the access to all reliable information related to the natural isotopic fractionation of both precursors and products. Natural abundance deuterium (NAD) 2D-NMR experiments in polypeptide liquid-crystalline solutions are a new, suitable tool for analyzing site-specific deuterium isotopic distribution profiles. Here this method is utilized for analyzing saturated C14 to C18 fatty acid methyl esters (FAMEs), which are challenging because of the crowding of signals in a narrow spectral region. Experiments in achiral and chiral oriented solutions were performed. The spectral analysis is supplemented by the theoretical prediction of quadrupolar splittings as a function of the geometry and flexibility of FAMEs, based on a novel computational methodology. This allows us to confirm the spectral assignments, while providing insights into the mechanism of solute ordering in liquid-crystalline polypeptide solutions. This is found to be dominated by steric repulsions between FAMEs and polypeptides.
authors.affiliation: RMN en Milieu Orienté, ICMMO, UMR-CNRS 8182, Université de Paris Sud 11, 91405 Orsay Cedex, France.
authors.forename: Zeinab
authors.initials: Z
authors.lastname: Serhan
authors.forename: Andrea
authors.initials: A
authors.lastname: Borgogno
authors.forename: Isabelle
authors.initials: I
authors.lastname: Billault
authors.forename: Alberta
authors.initials: A
authors.lastname: Ferrarini
authors.forename: Philippe
authors.initials: P
authors.lastname: Lesot
mesh_terms: D000465:Algorithms; D005227:Fatty Acids / Q000032:analysis* / Q000737:chemistry; D050866:Liquid Crystals; D008962:Models, Theoretical; D009243:NAD / Q000032:analysis; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D010455:Peptides / Q000032:analysis* / Q000737:chemistry
chemical_list: D005227:Fatty Acids; D010455:Peptides; D009243:NAD