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Inhibitory effects of HSP70 chaperones on nascent polypeptides
Author(s) -
Ryan Christine,
Schlesinger Milton J.,
Stevens Tom H.
Publication year - 1992
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1002/pro.5560010803
Subject(s) - hsp70 , heat shock protein , gene isoform , chaperone (clinical) , biochemistry , yeast , sindbis virus , protein folding , atpase , microbiology and biotechnology , chemistry , biology , translation (biology) , messenger rna , rna , enzyme , gene , medicine , pathology
Several of the major heat shock proteins (HSPs) function normally as molecular chaperones to prevent aggregation of immature polypeptides and thereby facilitate folding and oligomerization. To determine their effect on nascent polypeptides, we added purified preparations of different isoforms of HSP70 to in vitro translation reactions primed by the 26S mRNA of Sindbis virus, which encodes an autoprotease that functions cotranslationally, or by the mRNA encoding the yeast vacuolar H + ATPase, which is formed by a novel transpeptidase activity that removes the central region of the initial polypeptide. In the presence of HSP70s both the autoprotease and transpeptidase activities were inhibited, indicating that these chaperones can interact with nascent polypeptides and, in the cases studied here, perturb their normal structures.