1ZRU: Structure Of The Lactophage P2 Receptor Binding Protein In Complex With Glycerol

Phage p2, a member of the lactococcal 936 phage species, infects Lactococcus lactis strains by binding initially to specific carbohydrate receptors using its receptor-binding protein (RBP). The structures of p2 RBP, a homotrimeric protein composed of three domains, and of its complex with a neutralizing llama VH domain (VHH5) have been determined (S. Spinelli, A. Desmyter, C. T. Verrips, H. J. de Haard, S. Moineau, and C. Cambillau, Nat. Struct. Mol. Biol. 13:85-89, 2006). Here, we show that VHH5 was able to neutralize 12 of 50 lactococcal phages belonging to the 936 species. Moreover, escape phage mutants no longer neutralized by VHH5 were isolated from 11 of these phages. All of the mutations (but one) cluster in the RBP/VHH5 interaction surface that delineates the receptor-binding area. A glycerol molecule, observed in the 1.7-A resolution structure of RBP, was found to bind tightly (Kd= 0.26 microM) in a crevice located in this area. Other saccharides bind RBP with comparable high affinity. These data prove the saccharidic nature of the bacterial receptor recognized by phage p2 and identify the position of its binding site in the RBP head domain.
PDB ID: 1ZRUDownload
MMDB ID: 37949
PDB Deposition Date: 2005/5/22
Updated in MMDB: 2012/10
Experimental Method:
x-ray diffraction
Resolution: 1.73  Å
Source Organism:
Similar Structures:
Biological Unit for 1ZRU: trimeric; determined by author and by software (PISA)
Molecular Components in 1ZRU
Label Count Molecule
Proteins (3 molecules)
Lactophage P2 Receptor Binding Protein
Molecule annotation
Chemicals (6 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB