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Thermal unfolding of the N‐terminal region of p53 monitored by circular dichroism spectroscopy
Author(s) -
Schaub Leasha J.,
Campbell James C.,
Whitten Steven T.
Publication year - 2012
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1002/pro.2146
Subject(s) - circular dichroism , chemistry , proline , biophysics , protein secondary structure , crystallography , protein structure , intrinsically disordered proteins , protein tertiary structure , transcription (linguistics) , biology , biochemistry , amino acid , linguistics , philosophy
It has been estimated that 30% of eukaryotic protein and 70% of transcription factors are intrinsically disordered (ID). The biochemical significance of proteins that lack stable tertiary structure, however, is not clearly understood, largely owing to an inability to assign well‐defined structures to specific biological tasks. In an attempt to investigate the structural character of ID protein, we have measured the circular dichroism spectrum of the N‐terminal region of p53 over a range of temperatures and solution conditions. p53 is a well‐studied transcription factor that has a proline‐rich N‐terminal ID region containing two activation domains. High proline content is a property commonly associated with ID, and thus p53 may be a good model system for investigating the biochemical importance of ID. The spectra presented here suggest that the N‐terminal region of p53 may adopt an ordered structure under physiological conditions and that this structure can be thermally unfolded in an apparent two‐state manner. The midpoint temperature for this thermal unfolding of the N‐terminal region of p53 was at the near‐physiological temperature of 39°C, suggesting the possibility of a physiological role for the observed structural equilibrium.