Document Detail


Steroid binding activity is retained in a 16-kDa fragment of the steroid binding domain of rat glucocorticoid receptors.
MedLine Citation:
PMID:  2503518     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The steroid binding domain of the rat glucocorticoid receptor is considered as extending from amino acids 550 to 795. However, such a synthetic protein (i.e. amino acids 547-795; Mr approximately 31,000) has been reported to show very little affinity for the potent synthetic glucocorticoid dexamethasone. We now disclose that digestion of steroid-free rat glucocorticoid receptors with low concentrations of trypsin yields a single species, of Mr = 16,000, that is specifically labeled by dexamethasone 21-mesylate. This 16-kDa fragment retains high affinity binding for [3H]dexamethasone that is only approximately 23-fold lower than that seen with the intact 98-kDa receptor. Analysis of the protease digestion patterns obtained both with trypsin and with lysylendopeptidase C allowed us to deduce the proteolytic cleavage maps of the receptor with these enzymes. From these protease maps, the sequence of the 16-kDa fragment was identified as being threonine 537 to arginine 673. These results show that glucocorticoid receptor fragments smaller than 34 kDa do bind steroids and that the amino acids Thr537-Arg673 constitute a core sequence for ligand binding within the larger steroid binding domain. The much slower kinetics in generating the 16-kDa fragment from affinity-labeled receptors suggests that steroid binding causes a conformation change in the receptor near the cleavage sites.
Authors:
S S Simons; F D Sistare; P K Chakraborti
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  264     ISSN:  0021-9258     ISO Abbreviation:  J. Biol. Chem.     Publication Date:  1989 Aug 
Date Detail:
Created Date:  1989-09-13     Completed Date:  1989-09-13     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  14493-7     Citation Subset:  IM    
Affiliation:
Steroid Hormones Section, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892.
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MeSH Terms
Descriptor/Qualifier:
Amino Acid Sequence
Animals
Arginine
Binding, Competitive
Dexamethasone / analogs & derivatives,  metabolism*,  pharmacology
Hydrolysis
Molecular Weight
Protein Conformation
Rats
Receptors, Glucocorticoid / drug effects,  metabolism*
Serine Endopeptidases
Threonine
Trypsin
Chemical
Reg. No./Substance:
0/Receptors, Glucocorticoid; 2265-22-7/dexamethasone 21-methanesulfonate; 50-02-2/Dexamethasone; 72-19-5/Threonine; 74-79-3/Arginine; EC 3.4.21.-/Serine Endopeptidases; EC 3.4.21.4/Trypsin; EC 3.4.21.50/lysyl endopeptidase

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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