title: Bound water in apo and holo bovine heart fatty-acid-binding protein determined by heteronuclear NMR spectroscopy.
abstract: Two- and three-dimensional heteronuclear NMR experiments have been performed to identify internally bound water molecules in the solution structure of bovine heart fatty-acid-binding protein (heart FABP). NOE and rotating-frame NOE (ROE) cross peaks between protein protons and protons of bound water molecules were observed in two-dimensional H2O-ROE/NOE-1H,15N-heteronuclear single quantum coherence spectra recorded from a uniformly 13C/15N-enriched sample of bovine heart FABP. Contacts between water protons and 23 NH protons of the protein backbone were identified. The protein structure consists of 10 antiparallel beta-strands (betaA-betaJ), forming two nearly orthogonal beta-sheets, and a short helix-turn-helix motif connecting beta-strands A and B. The spatial folding resembles a beta-barrel. Most of the water molecules are localized in the gap between beta-strands D and E, and near the two alpha-helices. In the delipidated heart FABP additional contacts between water molecules and NH protons could be observed using a three-dimensional rotating frame Overhauser 1H,15N heteronuclear single quantum coherence experiment obtained with a 15N-labeled sample of apo-heart FABP.
authors.affiliation: Institut für Biophysikalische Chemie, Biozentrum, Frankfurt, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Mesgarzadeh
authors.forename: S
authors.initials: S
authors.lastname: Pfeiffer
authors.forename: J
authors.initials: J
authors.lastname: Engelke
authors.forename: D
authors.initials: D
authors.lastname: Lassen
authors.forename: H
authors.initials: H
authors.lastname: Rüterjans
mesh_terms: D000818:Animals; D001059:Apoproteins / Q000737:chemistry* / Q000378:metabolism; D002352:Carrier Proteins / Q000737:chemistry*; D002417:Cattle; D050556:Fatty Acid-Binding Proteins; D019077:Helix-Turn-Helix Motifs; D006859:Hydrogen; D008958:Models, Molecular; D018996:Myelin P2 Protein / Q000737:chemistry*; D009206:Myocardium / Q000378:metabolism*; D009363:Neoplasm Proteins; D009587:Nitrogen Isotopes; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods; D019308:Palmitic Acid / Q000378:metabolism; D017433:Protein Structure, Secondary; D014867:Water
chemical_list: D001059:Apoproteins; D002352:Carrier Proteins; D050556:Fatty Acid-Binding Proteins; D018996:Myelin P2 Protein; D009363:Neoplasm Proteins; D009587:Nitrogen Isotopes; D014867:Water; D019308:Palmitic Acid; D006859:Hydrogen