Source:http://linkedlifedata.com/resource/pubmed/id/18540681
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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
26
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| pubmed:dateCreated |
2008-6-24
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| pubmed:abstractText |
Multiprobe equilibrium unfolding experiments in the downhill regime (i.e., maximal barrier < 3 RT) can resolve the folding process with atomic resolution [ Munoz ( 2002) Int. J. Quantum Chem. 90, 1522 -1528] . Such information is extracted from hundreds of heterogeneous atomic equilibrium unfolding curves, which are characterized according to their denaturation midpoint (e.g., T m for thermal denaturation). Using statistical methods, we analyze T m accuracy when determined from the extremum of the derivative of the unfolding curve and from two-state fits under different sets of simulated experimental conditions. We develop simple procedures to discriminate between real unfolding heterogeneity at the atomic level and experimental uncertainty in the single T m of conventional two-state folding. We apply these procedures to the recently published multiprobe NMR experiments of BBL [ Sadqi et al. ( 2006) Nature 442, 317 -321 ] and conclude that for the 122 single transition atomic unfolding curves reported for this protein the mean T m accuracy is better than 1.8 K for both methods, compared to the 60 K spread in T m determined experimentally. Importantly, we also find that when the pre- or posttransition baseline is incomplete, the two-state fits systematically drift the estimated T m value toward the center of the experimental range. Therefore, the reported 60 K T m spread in BBL is in fact a lower limit. The derivative method is significantly less sensitive to this problem and thus is a better choice for multiprobe experiments with a broad T m distribution. The results we obtain in this work lay the foundations for the quantitative analysis of future multiprobe unfolding experiments in fast-folding proteins.
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| pubmed:grant | |
| pubmed:language |
eng
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| pubmed:journal | |
| pubmed:citationSubset |
IM
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| pubmed:chemical | |
| pubmed:status |
MEDLINE
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| pubmed:month |
Jul
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| pubmed:issn |
1520-4995
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| pubmed:author | |
| pubmed:issnType |
Electronic
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| pubmed:day |
1
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| pubmed:volume |
47
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| pubmed:owner |
NLM
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| pubmed:authorsComplete |
Y
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| pubmed:pagination |
6752-61
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| pubmed:meshHeading | |
| pubmed:year |
2008
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| pubmed:articleTitle |
Determining denaturation midpoints in multiprobe equilibrium protein folding experiments.
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| pubmed:affiliation |
Department of Chemistry and Biochemistry and Center for Biomolecular Structure and Organization, University of Maryland, College Park, Maryland 20742, USA. vmunoz@cib.csic.es
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| pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, Non-P.H.S.,
Research Support, Non-U.S. Gov't,
Research Support, N.I.H., Extramural
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