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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
25
pubmed:dateCreated
1986-3-26
pubmed:abstractText
A novel experiment is described for measurements of amide proton exchange rates in proteins with a time resolution of about 1 s. A flow apparatus was used to expose protein solutions in 2H2O first to high temperature for a predetermined time period, during which 1H-2H exchange proceeded, and then to ice-water. The technique was applied for exchange studies in thermally unfolded, selectively reduced basic pancreatic trypsin inhibitor. Measurements were made by 1H nuclear magnetic resonance after the exchange was quenched by rapid cooling. Thereby, the sequence-specific resonance assignments for the folded protein could be used, which had been previously obtained. The results of this study indicate that the exchange rates in the thermally unfolded protein are close to those expected for a random chain and that the NH exchange is catalyzed by 2H+ and O2H- up to high temperature, with no significant contributions from p2H-independent catalysis. We conclude that the parameters derived by Molday et al. [Molday, R. S., Englander, S. W., & Kallen, R. G. (1972) Biochemistry 11, 150-158] from measurements with small model peptides can be used to calculate intrinsic exchange rates in unfolded proteins and thus provide a reliable reference for the interpretation of exchange rates measured under native conditions.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
3
pubmed:volume
24
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
7407-11
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1985
pubmed:articleTitle
Individual amide proton exchange rates in thermally unfolded basic pancreatic trypsin inhibitor.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't