Structural framework for DNA translocation via the viral portal protein |
| |
Authors: | Lebedev Andrey A Krause Margret H Isidro Anabela L Vagin Alexei A Orlova Elena V Turner Joanne Dodson Eleanor J Tavares Paulo Antson Alfred A |
| |
Institution: | York Structural Biology Laboratory, Department of Chemistry, University of York, York, UK. |
| |
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. |
| |
Keywords: | |
本文献已被 PubMed 等数据库收录! |
|