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Reaction cycle of the yeast Isw2 chromatin remodeling complex
Author(s) -
Fitzgerald Daniel J,
DeLuca Carl,
Berger Imre,
Gaillard Hélène,
Sigrist Raphael,
Schimmele Kyoko,
Richmond Timothy J
Publication year - 2004
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1038/sj.emboj.7600364
Subject(s) - biology , chromatin , chromatin remodeling , yeast , genetics , saccharomyces cerevisiae , microbiology and biotechnology , dna
Members of the ISWI family of chromatin remodeling factors hydrolyze ATP to reposition nucleosomes along DNA. Here we show that the yeast Isw2 complex interacts with DNA in a nucleotide‐dependent manner at physiological ionic strength. Isw2 efficiently binds DNA in the absence of nucleotides and in the presence of a nonhydrolyzable ATP analog. Conversely, ADP promotes the dissociation of Isw2 from DNA. In contrast, Isw2 remains bound to mononucleosomes through multiple cycles of ATP hydrolysis. Solution studies show that Isw2 undergoes nucleotide‐dependent alterations in conformation not requiring ATP hydrolysis. Our results indicate that during an Isw2 remodeling reaction, hydrolysis of successive ATP molecules coincides with cycles of DNA binding, release, and rebinding involving elements of Isw2 distinct from those interacting with nucleosomes. We propose that progression of the DNA‐binding site occurs while nucleosome core contacts are maintained and generates a force dissipated by disruption of histone–DNA interactions.