Structural studies of mutant glucocorticoid receptor transactivation domains establish a link between transactivation activity in vivo and alpha-helix-forming potential in vitro.
We have previously shown, using circular dichroism spectroscopy, that the tau 1 core peptide has alpha-helix-forming potential in vitro [Dahlman-Wright et al. (1995) Proc. Natl. Acad. Sci. U.S.A. 92, 1699-1703]. The tau 1 core peptide is a 58-amino acid peptide, constituting the core of the transactivation activity of the tau 1 major transactivation domain of the human glucocorticoid receptor [Dahlman-Wright et al. (1994) Proc. Natl. Acad. Sci. U.S.A. 91, 1619-1623]. Further structural studies of the peptide, using NMR spectroscopy, identified three segments with alpha-helical character. In this report we show that reduced protein expression or stability is not responsible for the reduced in vivo transactivation potential of tau 1 core peptides with proline substitutions in proposed alpha-helical regions. Rather, the reduced alpha-helix propensity of the corresponding purified peptides in vitro suggests that alpha-helices are involved in the molecular mechanism of glucocorticoid receptor mediated changes in gene activity.
Dahlman-Wright
K
K
Department of Biosciences, NOVUM, Karolinska Institutet, Huddinge, Sweden.
McEwan
I J
IJ
D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D009154:Mutation; D011392:Proline / Q000737:chemistry; D017433:Protein Structure, Secondary; D011965:Receptors, Glucocorticoid / Q000737:chemistry* / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000737:chemistry; D012697:Serine Endopeptidases; D013329:Structure-Activity Relationship; D015533:Transcriptional Activation; D015003:Yeasts / Q000235:genetics; D000099160:LexA Repressor Protein
D001426:Bacterial Proteins; D011392:Proline; D011965:Receptors, Glucocorticoid; D011993:Recombinant Fusion Proteins; D012697:Serine Endopeptidases; D000099160:LexA Repressor Protein