Sensitivity-Enhanced Detection of Fast Exchanging Protons by an Exchange-Edited Gradient HEHAHA-HSQC Experiment
✍ Scribed by Klaus Zangger; Ian M. Armitage
- Publisher
- Elsevier Science
- Year
- 1998
- Tongue
- English
- Weight
- 119 KB
- Volume
- 135
- Category
- Article
- ISSN
- 1090-7807
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✦ Synopsis
An experiment is presented which allows for the sensitivity-enhanced measurement of proton exchange rates in a HSQC type experiment. Instead of using INEPT type transfer of magnetization from protons to heteronuclei and vice versa, we have used heteronuclear Hartmann-Hahn transfer, which is known to have higher sensitivity in the presence of chemical exchange. Direct NOE's between NH protons and alpha-protons are suppressed by an exchange-editing step unless the alpha-resonances are degenerate with the water resonance. A comparison between the exchange-edited HEHAHA-HSQC and a standard exchange-edited HSQC experiment performed on the uniformly 15N-labeled staphylococcal nuclease H124L shows an enhancement of approximately 100% with the former experiment. A set of one-dimensional exchange-edited spectra of urea was used for evaluating the ability to extract exchange rates using the presented experiment.