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Interaction of urea with an unfolded protein The DNA‐binding domain of the 434‐repressor
Author(s) -
Dötsch V.,
Wider G.,
Siegal G.,
Wüthrich K.
Publication year - 1995
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(95)00459-m
Subject(s) - urea , chemistry , solvation , aqueous solution , molecule , repressor , crystallography , nuclear overhauser effect , stereochemistry , biophysics , biochemistry , organic chemistry , transcription factor , biology , gene
Experimental techniques are presented for the observation of the solvation of the unfolded form of a globular protein, the N‐terminal 63‐residue polypeptide from the 434 repressor, in 7 M aqueous urea solution by both water and urea. With the use of 15 N‐labelled urea it is demonstrated that the cross sections through two‐dimensional nuclear Overhauser enhancement (NOE) spectra at the chemical shifts of H 2 O and urea both contain direct NOEs with the protein, under conditions where exchange peaks are observed only in the water cross section. A preliminary analysis of the data showed that the residence times of urea molecules in solvation sites near the methyl groups of Val, Leu and Ile are significantly longer than those of water molecules in the same sites.