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Local Transient Unfolding of Native State PAI‐1 Associated with Serpin Metastability
Author(s) -
Trelle Morten B.,
Madsen Jeppe B.,
Andreasen Peter A.,
Jørgensen Thomas J. D.
Publication year - 2014
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201402796
Subject(s) - serpin , metastability , chemistry , plasminogen activator inhibitor 1 , serine protease , hydrogen–deuterium exchange , biophysics , plasminogen activator , crystallography , protease , biochemistry , biology , mass spectrometry , enzyme , genetics , organic chemistry , chromatography , gene
The metastability of the native fold makes serpin (serine protease inhibitor) proteins prone to pathological conformational change, often by insertion of an extra β‐strand into the central β‐sheet A. How this insertion is made possible is a hitherto unresolved question. By the use of advanced hydrogen/deuterium‐exchange mass spectrometry (HDX‐MS) it is shown that the serpin plasminogen activator inhibitor 1 (PAI‐1) transiently unfolds under native condition, on a second‐to‐minute time scale. The unfolding regions comprise β‐strand 5A as well as the underlying hydrophobic core, including β‐strand 6B and parts of helices A, B, and C. Based thereon, a mechanism is proposed by which PAI‐1 makes transitions through progressively more unfolded states along the reaction coordinate to the inactive, so‐called latent form. Our results highlight the profound utility of HDX‐MS in detecting sparsely populated, transiently unfolded protein states.