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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
14
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pubmed:dateCreated |
1998-5-7
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pubmed:abstractText |
The solution structure of cardiac troponin C (cTnC) (Sia, S., Li, M. X., Spyracopoulos, L., Gagne, S. M., Liu, W., Putkey, J. A. & Sykes, B. D. (1997) J. Biol. Chem. 272, 18216-18221) challenges existing structure/function models for this critical regulatory protein. For example, it is clear that the closed conformation of the regulatory N-terminal domain in Ca2+-bound cardiac troponin C (cTnC) presents a much different binding surface for Ca2+-sensitizing compounds than previously thought. We report here the use of Met methyl groups as site-specific structural markers to identify drug binding sites for trifluoperazine and bepridil on cTnC. Drug dependent changes in the NMR heteronuclear single-quantum coherence spectra of [methyl-13C]Met-labeled cTnC indicate that bepridil and trifluoperazine bind to similar sites but only in the presence of Ca2+. There are 3-4 drug binding sites in the N- and C-terminal domains of intact cTnC that exhibit fast exchange on the NMR time scale. Use of a novel spin-labeled phenothiazine and detection of isotope-filtered nuclear Overhauser effects allowed identification of drug binding sites in the shallow hydrophobic cup in the C-terminal domain and on two hydrophobic surfaces on the N-terminal regulatory domain. The data presented here, coupled with our previous study using covalent blocking groups, support a model in which the Ca2+-sensitizing binding site includes Met-45 in helix B of site I, and Met-60 and -80 in helices B and C of the regulatory site II. This subregion in cTnC makes a likely target against which to design new and selective Ca2+-sensitizing compounds.
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pubmed:grant | |
pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
|
pubmed:chemical | |
pubmed:status |
MEDLINE
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pubmed:month |
Apr
|
pubmed:issn |
0021-9258
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:day |
3
|
pubmed:volume |
273
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
8153-60
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pubmed:dateRevised |
2007-11-14
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pubmed:meshHeading |
pubmed-meshheading:9525919-Animals,
pubmed-meshheading:9525919-Bepridil,
pubmed-meshheading:9525919-Binding Sites,
pubmed-meshheading:9525919-Calcium,
pubmed-meshheading:9525919-Humans,
pubmed-meshheading:9525919-Myocardium,
pubmed-meshheading:9525919-Protein Binding,
pubmed-meshheading:9525919-Protein Conformation,
pubmed-meshheading:9525919-Trifluoperazine,
pubmed-meshheading:9525919-Troponin C
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pubmed:year |
1998
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pubmed:articleTitle |
Identification of binding sites for bepridil and trifluoperazine on cardiac troponin C.
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pubmed:affiliation |
Department of Biochemistry and Molecular Biology, University of Texas Medical School, Houston, Texas 77030, USA.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.,
Research Support, Non-U.S. Gov't
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