Assignment of NH resonances in nucleic acids using natural abundance 15 N‐ 1 H correlation spectroscopy with spin‐echo and gradient pulses
1993; Wiley; Volume: 327; Issue: 3 Linguagem: Inglês
10.1016/0014-5793(93)81000-p
ISSN1873-3468
AutoresAlexander A. Szewczak, Greg Tucker‐Kellogg, Peter B. Moore,
Tópico(s)Enzyme Structure and Function
ResumoIt is well known that 2D 15 N‐ 1 H correlation spectra can resolve overlapped imino proton resonances in the downfleld NMR spectra of nucleic acids according to their 15 N chemical shifts, and that these resonances can be assigned by base type on that basis, independent of conformation. This information can be extremely important in determining the solution structure of a nucleic acid by NMR, but previously could only be obtained using 15 N‐labeled, or very concentrated samples. Here we report the design of a gradient‐enhanced, jump‐return spin echo version of an 15 N‐ 1 H HMQC experiment (GE‐JRSE HMQC) that is sensitive enough to work on unlabeled nucleic acid samples at normal NMR concentrations. This experiment has led to the assignment of imino proton resonances with non‐Watson‐Crick chemical shifts in the spectrum of a 29 residue oligoribonucleotide that models the sarcin/ricin loop from 28S rRNA.
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