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Crystal structure of Bacillus subtilis SPP1 phage gp23.1, a putative chaperone
Author(s) -
Veesler David,
Blangy Stéphanie,
Lichière Julie,
OrtizLombardía Miguel,
Tavares Paulo,
Campanacci Valérie,
Cambillau Christian
Publication year - 2010
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1002/pro.464
Subject(s) - random hexamer , bacillus subtilis , chaperone (clinical) , biology , crystallography , microbiology and biotechnology , chemistry , genetics , bacteria , medicine , pathology
SPP1 is a siphophage infecting the gram‐positive bacterium Bacillus subtilis . The SPP1 tail electron microscopy (EM) reconstruction revealed that it is mainly constituted by conserved structural proteins such as the major tail proteins (gp17.1), the tape measure protein (gp18), the Distal tail protein (Dit, gp19.1), and the Tail associated lysin (gp21). A group of five small genes (22–24.1) follows in the genome but it remains to be elucidated whether their protein products belong or not to the tail. Noteworthy, an unassigned EM density accounting for ∼245 kDa is present at the distal end of the SPP1 tail‐tip. We report here the gp23.1 crystal structure at 1.6 Å resolution, a protein that lacks sequence identity to any known protein. We found that gp23.1 forms a hexamer both in the crystal lattice and in solution as revealed by light scattering measurements. The gp23.1 hexamer does not fit well in the unassigned SPP1 tail‐tip EM density and we hypothesize that this protein might act as a chaperone.