Structure of the receptor-binding carboxy-terminal domain of the bacteriophage T5 L-shaped tail fibre with and without its intra-molecular chaperone

DOI: 10.3390/v7122946
PMID: 26670244

Authors: Carmela Garcia-Doval (Centro Nacional de Biotecnología, Espana) , José Castón (Centro Nacional de Biotecnología) , Daniel Luque (Centro Nacional de Biotecnología) , Meritxell Granell (Centro Nacional de Biotecnología) , José Otero (Universidade de Santiago de Compostela) , Antonio Llamas-Saiz (Universidade de Santiago de Compostela) , Madalena Renouard (CNRS) , Pascale Boulanger (CNRS) , Mark Van Raaij (Centro Nacional de Biotecnología, Spain)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Viruses , VOL 7 , PAGES 6424 - 6440

State: Published (Approved)
Published: December 2015
Diamond Proposal Number(s): 3808

Abstract: Bacteriophage T5, a Siphovirus belonging to the order Caudovirales, has a flexible, three-fold symmetric tail, to which three L-shaped fibres are attached. These fibres recognize oligo-mannose units on the bacterial cell surface prior to infection and are composed of homotrimers of the pb1 protein. Pb1 has 1396 amino acids, of which the carboxy-terminal 133 residues form a trimeric intra-molecular chaperone that is auto-proteolyzed after correct folding. The structure of a trimer of residues 970-1263 was determined by single anomalous dispersion phasing using incorporated selenomethionine residues and refined at 2.3 angstrom resolution using crystals grown from native, methionine-containing, protein. The protein inhibits phage infection by competition. The phage-distal receptor-binding domain resembles a bullet, with the walls formed by partially intertwined beta-sheets, conferring stability to the structure. The fold of the domain is novel and the topology unique to the pb1 structure. A site-directed mutant (Ser1264 to Ala), in which auto-proteolysis is impeded, was also produced, crystallized and its 2.5 angstrom structure solved by molecular replacement. The additional chaperone domain (residues 1263-1396) consists of a central trimeric alpha-helical coiled-coil flanked by a mixed alpha-beta domain. Three long beta-hairpin tentacles, one from each chaperone monomer, extend into long curved grooves of the bullet-shaped domain. The chaperone-containing mutant did not inhibit infection by competition.

Journal Keywords: bacterial viruses; Caudovirales; Siphoviridae; crystallography; infection; J0101

Diamond Keywords: Bacteriophages

Subject Areas: Biology and Bio-materials


Instruments: I02-Macromolecular Crystallography

Other Facilities: BL13-XALOC at ALBA

Added On: 16/02/2016 11:10

Documents:
viruses-07-02946.pdf

Discipline Tags:

Structural biology Life Sciences & Biotech

Technical Tags:

Diffraction Macromolecular Crystallography (MX)