title: Crystal structure of a chimeric receptor binding protein constructed from two lactococcal phages.
abstract: 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.
authors.affiliation: Architecture et Fonction des Macromolécules Biologiques, UMR 6098 CNRS, and Universités Aix-Marseille I & II, Campus de Luminy, Case 932, 13288 Marseille Cedex 09, France.
authors.forename: Marina
authors.initials: M
authors.lastname: Siponen
authors.forename: Silvia
authors.initials: S
authors.lastname: Spinelli
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Blangy
authors.forename: Sylvain
authors.initials: S
authors.lastname: Moineau
authors.forename: Christian
authors.initials: C
authors.lastname: Cambillau
authors.forename: Valérie
authors.initials: V
authors.lastname: Campanacci
mesh_terms: D001435:Bacteriophages / Q000378:metabolism*; D001665:Binding Sites; D018360:Crystallography, X-Ray / Q000379:methods*; D013294:Lactococcus lactis / Q000821:virology*; D010447:Peptide Hydrolases / Q000378:metabolism; D017433:Protein Structure, Secondary; D011993:Recombinant Fusion Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D014764:Viral Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
chemical_list: D011993:Recombinant Fusion Proteins; D014764:Viral Proteins; D010447:Peptide Hydrolases