Download MendeleyStructural Framework for DNA Translocation Via the Viral Portal Protein
Lebedev, A.A., Krause, M.H., Isidro, A.L., Vagin, A.A., Orlova, E.V., Turner, J., Dodson, E.J., Tavares, P., Antson, A.A.(2007) EMBO J 26: 1984
- PubMed: 17363899
- DOI: https://doi.org/10.1038/sj.emboj.7601643
- Primary Citation of Related Structures:
2JES - PubMed Abstract:
Tailed bacteriophages and herpesviruses load their capsids with DNA through a tunnel formed by the portal protein assembly. Here we describe the X-ray structure of the bacteriophage SPP1 portal protein in its isolated 13-subunit form and the pseudoatomic structure of a 12-subunit assembly. The first defines the DNA-interacting segments (tunnel loops) that pack tightly against each other forming the most constricted part of the tunnel; the second shows that the functional dodecameric state must induce variability in the loop positions. Structural observations together with geometrical constraints dictate that in the portal-DNA complex, the loops form an undulating belt that fits and tightly embraces the helical DNA, suggesting that DNA translocation is accompanied by a 'mexican wave' of positional and conformational changes propagating sequentially along this belt.
Organizational Affiliation:
York Structural Biology Laboratory, Department of Chemistry, University of York, York, UK.
