Crystal structure of a chimeric receptor binding protein constructed from two lactococcal phages

J Bacteriol. 2009 May;191(10):3220-5. doi: 10.1128/JB.01637-08. Epub 2009 Mar 13.


Lactococcus lactis, a gram-positive bacterium widely used by the dairy industry to manufacture cheeses, is subject to infection by a diverse population of virulent phages. We have previously determined the structures of three receptor binding proteins (RBPs) from lactococcal phages TP901-1, p2, and bIL170, each of them having a distinct host range. Virulent phages p2 and bIL170 are classified within the 936 group, while the temperate phage TP901-1 is a member of the genetically distinct P335 polythetic group. These RBPs comprise three domains: the N-terminal domain, binding to the virion particle; a beta-helical linker domain; and the C-terminal domain, bearing the receptor binding site used for host recognition. Here, we have designed, expressed, and determined the structure of an RBP chimera in which the N-terminal and linker RBP domains of phage TP901-1 (P335) are fused to the C-terminal RBP domain of phage p2 (936). This chimera exhibits a stable structure that closely resembles the parental structures, while a slight displacement of the linker made RBP domain adaptation efficient. The receptor binding site is structurally indistinguishable from that of native p2 RBP and binds glycerol with excellent affinity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacteriophages / metabolism*
  • Binding Sites
  • Crystallography, X-Ray / methods*
  • Lactococcus lactis / virology*
  • Peptide Hydrolases / metabolism
  • Protein Structure, Secondary
  • Recombinant Fusion Proteins / chemistry*
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Viral Proteins / chemistry*
  • Viral Proteins / genetics
  • Viral Proteins / metabolism


  • Recombinant Fusion Proteins
  • Viral Proteins
  • Peptide Hydrolases