title: Measurement of 2J(H,C)- and 3J(H,C)-coupling constants by alpha/beta selective HC(C)H-TOCSY.
abstract: A new heteronuclear NMR pulse sequence for the measurement of nJ(C,H) coupling constants, the alpha/beta selective HC(C)H-TOCSY, is described. It is shown that the S3E element (Meissner et al., 1997a,b) can be used to obtain spin state selective coherence transfer in molecules, in which adjacent CH moieties are labeled with 13C. Application of the alpha/beta selective HC(C)H-TOCSY to a 10 nt RNA tetraloop 5'-CGCUUUUGCG-3', in which the four uridine residues are 13C labeled in the sugar moiety, allowed measurement of two bond and three bond J(C,H) coupling constants, which provide additional restraints to characterize the sugar ring conformation of RNA in cases of conformational averaging.
authors.affiliation: Massachusetts Institute of Technology, Department of Chemistry, Cambridge 02139, USA.
authors.forename: E
authors.initials: E
authors.lastname: Duchardt
authors.forename: C
authors.initials: C
authors.lastname: Richter
authors.forename: B
authors.initials: B
authors.lastname: Reif
authors.forename: S J
authors.initials: SJ
authors.lastname: Glaser
authors.forename: J W
authors.initials: JW
authors.lastname: Engels
authors.forename: C
authors.initials: C
authors.lastname: Griesinger
authors.forename: H
authors.initials: H
authors.lastname: Schwalbe
mesh_terms: D001483:Base Sequence; D002247:Carbon Isotopes; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D009690:Nucleic Acid Conformation; D009843:Oligoribonucleotides / Q000737:chemistry
chemical_list: D002247:Carbon Isotopes; D009843:Oligoribonucleotides