Linked Life Data

15520004

Source:http://linkedlifedata.com/resource/pubmed/id/15520004

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2005-1-11
pubmed:abstractText
Fluorescence spectroscopy provides a direct method for evaluating the environment of a fluorescent ligand bound to its receptor. We utilized this methodology to determine the environment of Alexa within a cholecystokinin (CCK)-like probe (Alexa488-Gly-[(Nle(28,31))CCK-26-33]; CCK-8 probe) bound to the type A CCK receptor (Harikumar, K. G., Pinon, D. L., Wessels, W. S., Prendergast, F. G., and Miller, L. J. (2002) J. Biol. Chem. 277, 18552-18560). Here, we study this probe at the type B CCK receptor and develop another probe with its fluorophore closer to the carboxyl-terminal pharmacophore of type B receptor ligands (Alexa488-Trp-Nle-Asp-Phe-NH2; CCK-4 probe). Both probes bound to type B CCK receptors in a saturable and specific manner and represented full agonists. Similar to the type A receptor, at the type B receptor these probes exhibited shorter lifetimes and lower anisotropy when the receptor was in the active conformation than when it was shifted to its inactive, G protein-uncoupled state using guanosine 5'-[beta,gamma-imido]-triphosphate trisodium salt. Absolute values for lifetime and anisotropy were lower for the CCK-8 probe bound to the type B receptor than for this probe bound to the type A receptor, and Alexa fluorescence was more easily quenched by iodide at the type B receptor. This represents the first direct evidence that, despite having identical affinities for binding and potencies for activating type A and B receptors, CCK is docked via distinct mechanisms, with the amino terminus more exposed to the aqueous milieu when bound to the type B CCK receptor than to the type A CCK receptor. Of interest, despite this difference in binding, activation of both receptors results in analogous direction of movement of the fluorescent indicator probes.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
14
pubmed:volume
280
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1044-50
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2005
pubmed:articleTitle
Distinct molecular mechanisms for agonist peptide binding to types A and B cholecystokinin receptors demonstrated using fluorescence spectroscopy.
pubmed:affiliation
Cancer Center and Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic Scottsdale, Scottsdale, Arizona 85259, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't