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Unread 04-02-2007, 08:52 PM
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Default Peak height vs volume

I haven't seen any studies comparing structures calculated from peak heights or volumes but Peter Wright's group did analysis a few years ago about the differences in relaxation rates calculated from intensities and volumes as well as data fitting.

Viles JH, Duggan BM, Zaborowski E, Schwarzinger S, Huntley JJ, Kroon GJ, Dyson HJ, Wright PE. Related Articles, Links
Abstract Potential bias in NMR relaxation data introduced by peak intensity analysis and curve fitting methods.
J Biomol NMR. 2001 Sep;21(1):1-9.
PMID: 11693564 [PubMed - indexed for MEDLINE]

I believe they found that routines that found intensities by checking for the highest point in an area around a peak maximum biased the measurements to higher value because they were subject to influence of noise but that the results were otherwise quite similar. In my experience most people use intensities when they a large number of NOEs as in protein spectra and use volumes in combination with careful relaxation analysis/simulation routines (ie CORMA) where few distance constraints are available as is the case in DNA. For protein structures a large number of loose constraints serves to restrain the structure quite well and the extra time, difficulties and overlap problems of peak integration are not worth the trouble.
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