Cooperative conformational transitions keep reca filament active during ATPase cycle

Sung Hyun Kim, Kaushik Ragunathan, Jeehae Park, Chirlmin Joo, Doseok Kim, Taekjip Ha

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


The active, stretched conformation of the RecA filament bound to single-stranded DNA is required for homologous recombination. During this process, the RecA filament mediates the homology search and base pair exchange with a complementary sequence. Subsequently, the RecA filament dissociates from DNA upon reaction completion. ATP binding and hydrolysis is critical throughout these processes. Little is known about the timescale, order of conversion between different cofactor bound forms during ATP hydrolysis, and the associated changes in filament conformation. We used single-molecule fluorescence techniques to investigate how ATP hydrolysis is coupled with filament dynamics. For the first time, we observed real-time cooperative structural changes within the RecA filament. This cooperativity between neighboring monomers provides a time window for nucleotide cofactor exchange, which keeps the filament in the active conformation amidst continuous cycles of ATP hydrolysis.

Original languageEnglish
Pages (from-to)14796-14800
Number of pages5
JournalJournal of the American Chemical Society
Issue number42
StatePublished - 22 Oct 2014

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© 2014 American Chemical Society.


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