2X53: Structure of the phage p2 baseplate in its activated conformation with Sr

Citation:
Abstract
Siphoviridae is the most abundant viral family on earth which infects bacteria as well as archaea. All known siphophages infecting gram+ Lactococcus lactis possess a baseplate at the tip of their tail involved in host recognition and attachment. Here, we report analysis of the p2 phage baseplate structure by X-ray crystallography and electron microscopy and propose a mechanism for the baseplate activation during attachment to the host cell. This approximately 1 MDa, Escherichia coli-expressed baseplate is composed of three protein species, including six trimers of the receptor-binding protein (RBP). RBPs host-recognition domains point upwards, towards the capsid, in agreement with the electron-microscopy map of the free virion. In the presence of Ca(2+), a cation mandatory for infection, the RBPs rotated 200 degrees downwards, presenting their binding sites to the host, and a channel opens at the bottom of the baseplate for DNA passage. These conformational changes reveal a novel siphophage activation and host-recognition mechanism leading ultimately to DNA ejection.
PDB ID: 2X53Download
MMDB ID: 80074
PDB Deposition Date: 2010/2/5
Updated in MMDB: 2011/05
Experimental Method:
x-ray diffraction
Resolution: 3.9  Å
Source Organism:
Similar Structures:
Biological Unit for 2X53: 54-meric; determined by author and by software (PISA)
Molecular Components in 2X53
Label Count Molecule
Proteins (54 molecules)
6
Orf16
Molecule annotation
36
Putative Receptor Binding Protein
Molecule annotation
12
Orf15
Molecule annotation
Chemicals (12 molecules)
1
12
* Click molecule labels to explore molecular sequence information.

Citing MMDB
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