Source:http://linkedlifedata.com/resource/pubmed/id/11914085
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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
13
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| pubmed:dateCreated |
2002-3-26
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| pubmed:abstractText |
A cGMP-dependent protein kinase (PKG) was recently identified as an anticoccidial target for the apicomplexan parasite Eimeria tenella [Gurnett, A., Liberator, P. A., Dulski, P., Salowe, S., Donald, R. G. K., Anderson, J., Wiltsie, J., Diaz, C., Harris, G., Chang, B., Darkin-Rattray, S. J., Nare, B., Crumley, T., Blum, P., Misura, A., Tamas, T., Sardana, M., Yuan, J., Biftu, T., and Schmatz, D. (2002) J. Biol. Chem. (in press)]. Unlike the PKGs of higher organisms that have two cGMP binding sites in their regulatory domain, the PKG from Eimeria tenella (Et-PKG) contains three putative cGMP binding sites and has distinctive activation properties, including a very large stimulation by cGMP ( approximately 1000-fold) with significant cooperativity (Hill coefficient of 1.7). During our investigation of Et-PKG activation, we found that 8-substituted cGMP analogues are weak partial activators. For example, 8-NBD-cGMP provides a maximal stimulation of activity of only 20-fold with little evident cooperativity, although cGMP can synergize with the analogue to provide full activation. The results suggest that partial activation is a consequence of restricted binding of 8-NBD-cGMP to a subset of cGMP sites in the enzyme. Site-directed mutagenesis of conserved arginine and glutamate residues in the parasite-specific third cGMP site confirms that this site is an important functional participant in the allosteric regulation of the kinase and that it exhibits very high selectivity against 8-NBD-cGMP. Since the results are consistent with full activation of Et-PKG requiring cyclic nucleotide binding in all three allosteric sites, one role for the additional cGMP site may be to establish a stricter regulatory mechanism for the kinase activity than is present in the PKGs of higher organisms containing only two allosteric sites.
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| 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 |
Apr
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| pubmed:issn |
0006-2960
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| pubmed:author | |
| pubmed:issnType |
Print
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| pubmed:day |
2
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| pubmed:volume |
41
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| pubmed:owner |
NLM
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| pubmed:authorsComplete |
Y
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| pubmed:pagination |
4385-91
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| pubmed:dateRevised |
2009-11-19
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| pubmed:meshHeading |
pubmed-meshheading:11914085-Allosteric Site,
pubmed-meshheading:11914085-Amino Acid Sequence,
pubmed-meshheading:11914085-Animals,
pubmed-meshheading:11914085-Binding Sites,
pubmed-meshheading:11914085-Catalysis,
pubmed-meshheading:11914085-Coccidiostats,
pubmed-meshheading:11914085-Cyclic GMP-Dependent Protein Kinases,
pubmed-meshheading:11914085-Dose-Response Relationship, Drug,
pubmed-meshheading:11914085-Eimeria tenella,
pubmed-meshheading:11914085-Enzyme Activation,
pubmed-meshheading:11914085-Epitopes,
pubmed-meshheading:11914085-Kinetics,
pubmed-meshheading:11914085-Models, Chemical,
pubmed-meshheading:11914085-Molecular Sequence Data,
pubmed-meshheading:11914085-Mutagenesis, Site-Directed,
pubmed-meshheading:11914085-Protein Binding,
pubmed-meshheading:11914085-Protein Structure, Tertiary
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| pubmed:year |
2002
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| pubmed:articleTitle |
The role of a parasite-specific allosteric site in the distinctive activation behavior of Eimeria tenella cGMP-dependent protein kinase.
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| pubmed:affiliation |
Department of High Throughput Screening and Automation, Merck & Co., Inc., P.O. Box 2000, Rahway, New Jersey 07065, USA. scott_salowe@merck.com
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| pubmed:publicationType |
Journal Article
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