| Literature DB >> 16490212 |
Rafael Núñez-Ramírez1, Yolanda Robledo, Pablo Mesa, Silvia Ayora, Juan Carlos Alonso, José María Carazo, Luis Enrique Donate.
Abstract
Quaternary polymorphism is a distinctive structural feature of the DnaB family of replicative DNA hexameric helicases. The Bacillus subtilis bacteriophage SPP1 gene 40 product (G40P) belongs to this family. Three different quaternary states have been described for G40P homohexamers, two of them with C(3) symmetry, and the other with C(6) symmetry. We present three-dimensional reconstructions of the different architectures of G40P hexamers and a variant lacking the N-terminal domain. Comparison of the G40P and the deletion mutant structures sheds new light on the functional roles of the N and C-terminal domains, at the same time that it allows the direct structural mapping of these domains. Based on this new information, hybrid EM/X-ray models are presented for all the different symmetries. These results suggest that quaternary polymorphism of hexameric helicases may be implicated in the translocation along the DNA.Entities:
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Year: 2006 PMID： 16490212 DOI： 10.1016/j.jmb.2006.01.091
Source DB: PubMed Journal: J Mol Biol ISSN： 0022-2836 Impact factor: 5.469