ISSN:
1573-5001
Keywords:
Pulsed-field-gradient NMR
;
Translational diffusion coefficient
;
Self-association
;
Macromolecules
;
Solvent suppression
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Abstract We have previously shown that 1H pulsed-field-gradient(PFG) NMR spectroscopy provides a facile method for monitoring proteinself-association and can be used, albeit with some caveats, to measure theapparent molecular mass of the diffusant [Dingley et al. (1995) J. Biomol.NMR, 6, 321–328]. In this paper we show that, for15N-labelled proteins, selection of1H-15N multiple-quantum (MQ) coherences in PFGdiffusion experiments provides several advantages over monitoring1H single-quantum (SQ) magnetization. First, the use of agradient-selected MQ filter provides a convenient means of suppressingresonances from both the solvent and unlabelled solutes. Second,1H-15N zero-quantum coherence dephases morerapidly than 1H SQ coherence under the influence of a PFG.This allows the diffusion coefficients of larger proteins to be measuredmore readily. Alternatively, the gradient length and/or the diffusion delaymay be decreased, thereby reducing signal losses from relaxation. In orderto extend the size of macromolecules to which these experiments can beapplied, we have developed a new MQ PFG diffusion experiment in which themagnetization is stored as longitudinal two-spin order for most of thediffusion period, thus minimizing sensitivity losses due to transverserelaxation and J-coupling evolution.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1018339526108
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