Ultrastructural analysis of bacteriophage Φ29 during infection of Bacillus subtilis.

摘要: Recent advances in cryo-electron tomography (cryo-ET) have allowed direct visualization of the initial interactions between bacteriophages and their hosts. Previous studies focused on phage infection Gram-negative bacteria but it is particular interest how phages penetrate thick, highly cross-linked Gram-positive cell wall. Here we detail structural intermediates Φ29 during Bacillus subtilis. Use a minicell-producing strain facilitated situ tomographic reconstructions infecting particles. initially contacts wall at an angle through subset twelve appendages, which are attached to collar head proximal portion tail knob. The appendages flexible switch extended downward conformations this stage reversible adsorption; enzymatically hydrolyze teichoic acids bring closer cell. A wall-degrading enzyme distal tip knob locally digests peptidoglycan, facilitating penetration further into wall, particle reorients so that becomes perpendicular surface. All attain same "down" conformation adsorption. Once has become totally embedded can fuse with cytoplasmic membrane. membrane bulges out, presumably facilitate genome ejection cytoplasm, deformation remains after complete ejection. This study provides first changes occurring adsorption transfer bacterium.