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Title: Structural organization of the human glucocorticoid receptor determined by one- and two-dimensional gel electrophoresis of proteolytic receptor fragments

Journal Article · · Biochemistry; (United States)
DOI:https://doi.org/10.1021/bi00376a041· OSTI ID:6521558

The structural organization of the steroid-binding protein of the IM-9 cell glucocorticoid receptor was investigated by using one- and two-dimensional gel electrophoresis of proteolytic receptor fragments. One-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of receptor fragments isolated after trypsin digestion of immunopurified (/sup 3/H)dexamethasone 21-mesylate ((/sup 3/H)DM-) labeled receptor revealed the presence of a stable 26.5-kilodalton (kDa) steroid-containing non-DNA-binding fragment, derived from a larger, less stable, 29-kDa fragment. The 26.5-kDa tryptic fragment appeared to be completely contained within a 41-kDa, steroid-containing, DNA-binding species isolated after chymotrypsin digestion of the intact protein. Two-dimensional electrophoretic analysis of the (/sup 3/H)DM-labeled tryptic fragments resolved two 26.5-kDa and two 29-kDa components. This was the same number of isoforms seen in the intact protein, indicating that the charge heterogeneity of the steroid-binding protein is the result of modification within the steroid-containing, non-DNA-binding, 26.5-kDa tryptic fragment. Two-dimensional analysis of the 41-kDa (/sup 3/H)DM-labeled chymotryptic species revealed a pattern of isoforms more complex than that seen either in the intact protein or in the steroid-containing tryptic fragments. These results suggest that the 41-kDa (/sup 3/H)DM-labeled species resolved by one-dimensional SDS-PAGE after chymotrypsin digestion may be composed of several distinct proteolytic fragments.

Research Organization:
Uniformed Services Univ. of the Health Sciences, Bethesda, MD
OSTI ID:
6521558
Journal Information:
Biochemistry; (United States), Vol. 26:2
Country of Publication:
United States
Language:
English