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Association of HSP70 with endonucleases allows the expression of otherwise silent mutations
Author(s) -
Mizumura Hikaru,
Shibata Takehiko,
Morishima Nobuhiro
Publication year - 2002
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/s0014-5793(02)02925-3
Subject(s) - endonuclease , biology , hsp70 , saccharomyces cerevisiae , enzyme , yeast , cleavage (geology) , recognition sequence , biochemistry , mutation , genetics , peptide sequence , dna , microbiology and biotechnology , heat shock protein , gene , restriction enzyme , paleontology , fracture (geology)
A subpopulation of the 70 kDa heat shock protein (HSP70) found within the mitochondria of Saccharomyces cerevisiae functions as a stable binding partner of the endonuclease Sce I. We have previously found that the Sce I endonuclease monomer recognizes and cleaves a unique, 26 bp sequence in vitro. Dimerization with HSP70 changes the specificity of Sce I, allowing it to cleave at multiple sequences. This study shows that Suv I, an ortholog of Sce I isolated from a different yeast strain, contains two amino acid substitutions, yet it shows the same uni‐site specificity in its monomeric form. Binding of HSP70 to the Suv I monomer confers multi‐site specificity that is different from that exhibited by the HSP70/ Sce I heterodimer. Mutation of single residues of Sce I to the corresponding residue in Suv I provides enzymes with specificities intermediate between Sce I and Suv I when complexed with HSP70. These results suggest that HSP70 interaction with certain endonucleases allows the expression of otherwise silent mutations in them, causing a change in enzyme cleavage specificity.