A topological model of the baseplate of lactococcal phage Tuc2009.
Phages infecting Lactococcus lactis, a Gram-positive bacterium, are a recurrent problem in the dairy industry. Despite their economical importance, the knowledge on these phages, belonging mostly to Siphoviridae, lags behind that accumulated for members of Myoviridae. The three-dimensional structures of the receptor-binding proteins (RBP) of three lactococcal phages have been determined recently, illustrating their modular assembly and assigning the nature of their bacterial receptor. These RBPs are attached to the baseplate, a large phage organelle, located at the tip of the tail. Tuc2009 baseplate is formed by the products of 6 open read frames, including the RBP. Because phage binding to its receptor induces DNA release, it has been postulated that the baseplate might be the trigger for DNA injection. We embarked on a structural study of the lactococcal phages baseplate, ultimately to gain insight into the triggering mechanism following receptor binding. Structural features of the Tuc2009 baseplate were established using size exclusion chromatography coupled to on-line UV-visible absorbance, light scattering, and refractive index detection (MALS/UV/RI). Combining the results of this approach with literature data led us to propose a "low resolution" model of Tuc2009 baseplate. This model will serve as a knowledge base to submit relevant complexes to crystallization trials.
Architecture et Fonction des Macromolécules Biologiques, UMR 6098 CNRS, 163 Avenue de Luminy Case 932, Marseille Cedex 09, France.
Giuliano
G
Sciara
Stéphanie
S
Blangy
Marina
M
Siponen
Stephen
S
Mc Grath
Douwe
D
van Sinderen
Mariella
M
Tegoni
Christian
C
Cambillau
Valérie
V
Campanacci
D019143:Evolution, Molecular; D013294:Lactococcus lactis / Q000821:virology*; D008027:Light; D008958:Models, Molecular; D008970:Molecular Weight; D046912:Multiprotein Complexes; D016366:Open Reading Frames; D012542:Scattering, Radiation; D017906:Siphoviridae / Q000737:chemistry* / Q000235:genetics / Q000648:ultrastructure; D013056:Spectrophotometry, Ultraviolet; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics; D053585:Virus Attachment
D046912:Multiprotein Complexes; D014764:Viral Proteins