ISSN:
1573-5001
Keywords:
CI2
;
chemical exchange
;
constant-time
;
hydration
;
lysozyme
;
NOE
;
quadrature detection
;
ROE
;
water
;
water flip-back
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Abstract A pulse sequence is proposed to select water magnetization with enhanced specificity through a synergetic combination of several filtering principles. This approach relies on a constant-time evolution period implemented without quadrature detection, which results in a √2 increase in signal-to-noise ratios as compared to traditional non-selective methods for water filtration. In addition, the quadrature-free constant-time block facilitates the implementation of the water flip-back strategy, which leads to further gains in sensitivity. The proposed experiment was applied to unlabeled HEW lysozyme and to 15 N-labeled chymotrypsin inhibitor 2 which was partially or non 13C-enriched. Water molecules belonging to a spine of hydration between two pseudo β-sheet strands were identified, solving previously reported discrepancies between the X-ray and the refined NMR structure of CI2. The proposed experiment is particularly suitable for hydration studies of mixtures of labeled and unlabeled components, such as ligand–macromolecule complexes.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1008316612907
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