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Thermally‐induced structural changes in an armadillo repeat protein suggest a novel thermosensor mechanism in a molecular chaperone
Author(s) -
Bujalowski Paul J.,
Nicholls Paul,
Barral José M.,
Oberhauser Andres F.
Publication year - 2015
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/j.febslet.2014.11.034
Subject(s) - chaperone (clinical) , myosin , sarcomere , heat shock protein , protein folding , microbiology and biotechnology , biophysics , armadillo , heat stress , hsp90 , heat shock , chemistry , biology , biochemistry , gene , myocyte , medicine , zoology , pathology
Molecular chaperones are commonly identified by their ability to suppress heat‐induced protein aggregation. The muscle‐specific molecular chaperone UNC‐45B is known to be involved in myosin folding and is trafficked to the sarcomeres A‐band during thermal stress. Here, we identify temperature‐dependent structural changes in the UCS chaperone domain of UNC‐45B that occur within a physiologically relevant heat‐shock range. We show that distinct changes to the armadillo repeat protein topology result in exposure of hydrophobic patches, and increased flexibility of the molecule. These rearrangements suggest the existence of a novel thermosensor within the chaperone domain of UNC‐45B. We propose that these changes may function to suppress aggregation under stress by allowing binding to a wide variety of aggregation prone loops on its client.