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-Structure paper
タイトル | Loading a ring: structure of the Bacillus subtilis DnaB protein, a co-loader of the replicative helicase. |
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ジャーナル・号・ページ | J Mol Biol, Vol. 367, Issue 3, Page 764-769, Year 2007 |
掲載日 | 2007年3月30日 |
![]() | Rafael Núñez-Ramírez / Marion Velten / Germán Rivas / Patrice Polard / José María Carazo / Luis Enrique Donate / ![]() |
PubMed 要旨 | Loading of the ring-shaped replicative helicase is a critical step in the initiation of DNA replication. Bacillus subtilis has adopted a two-protein strategy to load its hexameric replicative ...Loading of the ring-shaped replicative helicase is a critical step in the initiation of DNA replication. Bacillus subtilis has adopted a two-protein strategy to load its hexameric replicative helicase: DnaB and DnaI interact with the helicase and mediate its delivery onto DNA. We present here the 3D electron microscopy structure of the DnaB protein, along with a detailed analysis of both its oligomeric state and its domain organization. DnaB is organized as an asymmetric tetramer that is comprised of two stacked components, one arranged as a closed collar and the other as an open sigma shape. Intriguingly, the 3D map of DnaB exhibits an overall architecture similar to the structure of the Escherichia coli gamma-complex, the loader of the ring-shaped processivity factor. We propose a model whereby each DnaB monomer participates in both stacked components of the tetramer and displays a different overall shape. This asymmetric quaternary organization could be a general feature of ring loaders. |
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手法 | EM (単粒子) |
解像度 | 24.0 Å |
構造データ | ![]() EMDB-1225: |
由来 |
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