title: An intraresidual i(HCA)CO(CA)NH experiment for the assignment of main-chain resonances in 15N, 13C labeled proteins.
abstract: An improved pulse sequence, intraresidual i(HCA)CO(CA)NH, is described for establishing solely (13)C'(i), (15)N(i), (1)HN(i) connectivities in uniformly 15N/13C-labeled proteins. In comparison to the "out-and-back" style intra-HN(CA)CO experiment, the new pulse sequence offers at least two-fold higher experimental resolution in the (13)C' dimension and on average 1.6 times higher sensitivity especially for residues in alpha-helices. Performance of the new experiment was tested on a small globular protein ubiquitin and an intrinsically unfolded 110-residue cancer/testis antigen CT16/PAGE5. Use of intraresidual i(HCA)CO(CA)NH experiment in combination with the established HNCO experiment was crucial for the assignment of highly disordered CT16.
authors.affiliation: Program in Structural Biology and Biophysics, Institute of Biotechnology/NMR Laboratory, University of Helsinki, P.O. Box 65, 00014 Helsinki, Finland.
authors.forename: Sampo
authors.initials: S
authors.lastname: Mäntylahti
authors.forename: Helena
authors.initials: H
authors.lastname: Tossavainen
authors.forename: Maarit
authors.initials: M
authors.lastname: Hellman
authors.forename: Perttu
authors.initials: P
authors.lastname: Permi
mesh_terms: D002247:Carbon Isotopes / Q000737:chemistry*; D006801:Humans; D009587:Nitrogen Isotopes / Q000737:chemistry*; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D011506:Proteins / Q000737:chemistry*; D025801:Ubiquitin / Q000737:chemistry
chemical_list: D002247:Carbon Isotopes; D009587:Nitrogen Isotopes; D011506:Proteins; D025801:Ubiquitin