S3E-E.COSY Methods for the Measurement of 19F Associated Scalar and Dipolar Coupling Constants

Published

September 1, 2001

Author(s)

B. Luy, J J. Barchi, John Marino

Abstract

A 1H-19F spin state selective excitation (S3E) pulse sequence element has been applied in combination with 1H homonuclear mixing to create E.COSY-type experiments designed to measure scalar JHF2' and JHH2' and residual dipolar DHF2' and DHH2' couplings in 2'-deoxy-2'-fluoro-sugars. The 1H-19F S3E pulse sequence element, which resembles a simple INEPT sequence, achieves spin-state-selective correlation between geminal 1H-19F spin pairs by linear combination of in-phase 19F magnetization and anti-phase magnetization evolved from 1H. Since the S3E sequence converts both 19F and 1H steady state polarization into observable coherences, an approximately two-fold signal increase is observed for fully relaxed 1H-19F spin pairs, with respect to a standard 1H coupled 19F 1D experiment. The improved sensitivity and resolution afforded by the use of 1H-19F S3E E.COSY-type experiments for measuring couplings is demonstrated on the nucleoside 9-(2',3'-dideoxy-2'-fluoro-b-D-threo-pentofuranosyl)adenine (b-FddA) and on a selectively 2'-fluorine labeled 21mer RNA oligonucleotide.

Citation

Journal of Magnetic Resonance

Volume

152

Issue

No. 1

Pub Type

Journals

Keywords

fluorine, residual dipolar couplings, RNA, S³E-E.COSY, scalar couplings

Citation

Luy, B. , Barchi, J. and Marino, J. (2001), S³E-E.COSY Methods for the Measurement of ¹⁹F Associated Scalar and Dipolar Coupling Constants, Journal of Magnetic Resonance (Accessed December 6, 2024)