Nature Structural & Molecular Biology
- 13, 676 - 683 (2006)
Published online: 9 July 2006; | doi:10.1038/nsmb1115
Structural basis for ATP-dependent DnaA assembly and replication-origin remodelingJan P Erzberger, Melissa L Mott & James M Berger
Division of Biochemistry and Molecular Biology, Molecular and Cell Biology Department, 327B Hildebrand Hall #3206, University of California, Berkeley, California 94720.
Correspondence should be addressed to James M Berger jmberger@berkeley.edu In bacteria, the initiation of replication is controlled by DnaA, a member of the ATPases associated with various cellular activities (AAA+) protein superfamily. ATP binding allows DnaA to transition from a monomeric state into a large oligomeric complex that remodels replication origins, triggers duplex melting and facilitates replisome assembly. The crystal structure of AMP-PCP–bound DnaA reveals a right-handed superhelix defined by specific protein-ATP interactions. The observed quaternary structure of DnaA, along with topology footprint assays, indicates that a right-handed DNA wrap is formed around the initiation nucleoprotein complex. This model clarifies how DnaA engages and unwinds bacterial origins and suggests that additional, regulatory AAA+ proteins engage DnaA at filament ends. Eukaryotic and archaeal initiators also have the structural elements that promote open-helix formation, indicating that a spiral, open-ring AAA+ assembly forms the core element of initiators in all domains of life.
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