title: Sequence-specific resonance assignment and secondary structure of (1-71) bacterioopsin.
abstract: The conformation of chymotryptic fragment C2 of bacteriohodopsin (residues 1-71) was studied by 2D 1H NMR. The fragment was solubilized in a mixture of chloroform/methanol (1:1), 0.1 M LiClO4. Most of the resonances in 1H NMR spectra of fragment C2 were assigned using phase-sensitive DQF-COSY, TOCSY, and NOESY techniques. To simplify the assignment procedure for overlapping regions of NMR spectra, an analog of fragment C2 with leucines deuterated in beta-positions was used. Deuterium exchange rates for amide protons were measured in a series of TOCSY spectra. Two right-handed alpha-helical regions Pro8-Lys30 and Lys41-Leu62 were identified on the basis of NOE connectivities and deuterium exchange rates. The N-terminal part of the fragment (Ala2-Gly6) adopts the helical conformation stabilized by 3 hydrogen bonds.
authors.affiliation: Shemyakin Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow.
authors.forename: A G
authors.initials: AG
authors.lastname: Sobol
authors.forename: A S
authors.initials: AS
authors.lastname: Arseniev
authors.forename: G V
authors.initials: GV
authors.lastname: Abdulaeva
authors.lastname: Musina LYu
authors.forename: V F
authors.initials: VF
authors.lastname: Bystrov
mesh_terms: D000595:Amino Acid Sequence; D001436:Bacteriorhodopsins / Q000737:chemistry*; D019617:Halobacterium salinarum / Q000378:metabolism; D006859:Hydrogen; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry; D011487:Protein Conformation
chemical_list: D010446:Peptide Fragments; D001436:Bacteriorhodopsins; C017827:bacterio-opsin; D006859:Hydrogen