Measurement of long-range 1H-19F scalar coupling constants and their glycosidic torsion dependence in 5-fluoropyrimidine-substituted RNA.
Long-range scalar 5J(H1',F) couplings were observed in 5-fluoropyrimidine-substituted RNA. We developed a novel S3E-19F-alpha,beta-edited NOESY experiment for quantitation of these long-range scalar 5J(H1',F) couplings, where the J-couplings can be extracted from inspection of intraresidual (H1',H6) NOE cross-peaks. Quantum chemical calculations were exploited to investigate the relation between scalar couplings and conformations around the glycosidic bond in oligonucleotides. The theoretical dependence of the observed 5J(H1',F) couplings on the torsion angle chi can be described by a generalized Karplus relationship. The corresponding density functional theory (DFT) analysis is outlined. Additional NMR experiments facilitating the resonance assignments of 5-fluoropyrimidine-substituted RNAs are described, and chemical shift changes due to altered shielding in the presence of fluorine-19 (19F) are presented.
Hennig
Mirko
M
Department of Molecular Biology and The Skaggs Institute of Chemical Biology, The Scripps Research Institute, MB 33, 10550 North Torrey Pines Road, La Jolla, California 92037, USA. mirko@scripps.edu
Munzarova
Markéta L
ML
Bermel
Wolfgang
W
Scott
Lincoln G
LG
Sklenar
Vladimír
V
Williamson
James R
JR
D006027:Glycosides / Q000737:chemistry*; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular; D011743:Pyrimidines / Q000737:chemistry*; D012313:RNA / Q000737:chemistry*
D006027:Glycosides; D011743:Pyrimidines; D012313:RNA; C029269:5-fluoropyrimidine