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Proline isomerization during refolding of ribonuclease A is accelerated by the presence of folding intermediates
Author(s) -
Schmid Franz X.
Publication year - 1986
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(86)80408-2
Subject(s) - isomerization , chemistry , ribonuclease , folding (dsp implementation) , protein folding , proline , native state , stereochemistry , photochemistry , crystallography , biochemistry , catalysis , amino acid , rna , electrical engineering , gene , engineering
The trans → cis isomerization of Pro 93 was measured during refolding of bovine ribonuclease A. This isomerization is slow (τ = 500s) under marginally stable folding conditions of 2.0 M GdmCl, pH 6, at 10°C. However, it is strongly accelerated (τ = 100 s) in samples which, prior to isomerization, had been converted to a folding intermediate by a 15s refolding pulse under strongly native conditions (0.8 M ammonium sulfate, 0°C). The results demonstrate that extensive folding is possible before Pro 93 isomerizes to its native cis state and that the presence of structural folding intermediates leads to a marked increase in the rate of subsequent proline isomerization.