Premium
Reversible denaturation of cyclosporin synthetase by urea
Author(s) -
Dittmann Joachim,
Vaillant François,
Kleinkauf Horst,
Lawen Alfons
Publication year - 1996
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(96)00014-2
Subject(s) - urea , denaturation (fissile materials) , chemistry , enzyme , biochemistry , conformational change , folding (dsp implementation) , fluorescence , stereochemistry , biophysics , biology , nuclear chemistry , physics , quantum mechanics , electrical engineering , engineering
The reversible denaturation of the multifunctional polypeptide, cyclosporin synthetase, by urea was analyzed. It is possible to discriminate between at least two stages of enzyme denaturation. While at low urea concentration (up to 0.8 M) cyclosporin A formation is inhibited, synthesis of the diketopiperazine cyclo ‐( ), a molecule representing a partial sequence of cyclosporin A is still detectable. At higher concentrations of urea the enzyme preparation is totally inactive. This inactivation is a consequence of conformational change(s) of cyclosporin synthetase as shown by fluorescence emission spectra of native and denatured enzyme. These data imply a consecutive folding/defolding mechanism for the different domains forming the multifunctional polypeptide.