title: Two-dimensional NMR studies of Kazal proteinase inhibitors. 1. Sequence-specific assignments and secondary structure of turkey ovomucoid third domain.
abstract: Two-dimensional proton NMR experiments have been used to sequentially assign resonances to all of the peptide backbone protons of turkey ovomucoid third domain (OMTKY3) except those of the N-terminal alpha-amino group whose signal was not resolved owing to exchange with the solvent. Assignments also have been made for more than 80% of the side-chain protons. Two-dimensional chemical shift correlated spectroscopy (COSY), relayed coherence transfer spectroscopy (RELAY), and two-dimensional homonuclear Hartmann-Hahn spectroscopy (HOHAHA) were used to identify the spin systems of almost half of the residues prior to sequential assignment. Assignments were based on two-dimensional nuclear Overhauser enhancements observed between adjacent residues. The secondary structure of OMTKY3 in solution was determined from additional assigned NOESY cross-peaks; it closely resembles the secondary structure determined by single-crystal X-ray diffraction of OMTKY3 in complex with Streptomyces griseus proteinase B [Fujinaga, M., Read, R.J., Sielecki, A., Ardelt, W., Laskowski, M., Jr., & James, M.N.G. (1982) Proc. Natl. Acad. Sci. U.S.A. 79, 4868-4872]. The NMR data provide evidence for three slowly exchanging amide protons that were not identified as hydrogen-bond donors in the crystal structure.
authors.affiliation: Department of Biochemistry, College of Agricultural and Life Sciences, University of Wisconsin, Madison 53706.
authors.forename: A D
authors.initials: AD
authors.lastname: Robertson
authors.forename: W M
authors.initials: WM
authors.lastname: Westler
authors.forename: J L
authors.initials: JL
authors.lastname: Markley
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D004527:Egg Proteins; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008969:Molecular Sequence Data; D010059:Ovomucin; D011487:Protein Conformation; D012697:Serine Endopeptidases; D015842:Serine Proteinase Inhibitors; D014422:Turkeys
chemical_list: D004527:Egg Proteins; D015842:Serine Proteinase Inhibitors; D010059:Ovomucin; D012697:Serine Endopeptidases; C028344:glutamyl endopeptidase