title: NMR signal assignments of amide protons in the alpha-helical domains of staphylococcal nuclease.
abstract: We report complete assignments of the amide proton signals in the three long dNN connectivity sequences observed in the NOESY spectrum of deuteriated staphylococcal nuclease (Nase) complexed with thymidine 3',5'-bisphosphate (pdTp) and Ca2+, Mr 18K. The assignments are made by comparing NOESY spectra with 1H-15N and 1H-13C heteronuclear multiple-quantum shift correlation (HMQC) spectra of Nase samples containing 15N- and 13C-labeled amino acids. The assignments show that the residues which are linked by the dNN connectivity sequences are located in three alpha-helical domains of Nase. Our results indicate that by combining NOESY and HMQC spectra of appropriately labeled samples it should be possible to delineate and study alpha-helical domains in soluble proteins having molecular weights that are greater than 18K.
authors.affiliation: Bone Research Branch, National Institute of Dental Research, Bethesda, Maryland 20892.
authors.forename: D A
authors.initials: DA
authors.lastname: Torchia
authors.forename: S W
authors.initials: SW
authors.lastname: Sparks
authors.forename: A
authors.initials: A
authors.lastname: Bax
mesh_terms: D000577:Amides; D009682:Magnetic Resonance Spectroscopy; D008836:Micrococcal Nuclease; D011522:Protons
chemical_list: D000577:Amides; D011522:Protons; D008836:Micrococcal Nuclease