Baseplate structure of bacteriophage phi812 reveals mechanism of cell wall binding and penetration
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| Year of publication | 2021 |
| Type | Conference abstract |
| MU Faculty or unit | |
| Citation | |
| Description | Antibiotic-resistant strains of Staphylococcus aureus cause human infections that are difficult to treat and can lead to death. Bacteriophage (phage) phi812K1/420 from the family Myoviridae infects 95% of clinical isolates of S. aureus and therefore is a promising candidate for a phage therapy agent . As the native phage particle approaches its host cell, phage receptor-binding proteins make a contact with the host cell wall. This interaction triggers a cascade of structural changes in the baseplate, resulting in phage tail contraction and genome ejection . Mechanistic description of the baseplate re-organization, however, remains unknown. Using cryo-electron microscopy (cryo-EM), we reconstructed the phage baseplate in native and contracted states (Fig. 1). The reconstruction of native baseplate reaches resolution of 4-5 A and we are in process of building individual protein structures. Also, selected proteins involved in host cell wall attachment and degradation were produced in recombinant form and their structures were solved using X-ray crystallography and cryo-EM single-particle reconstruction. The protein structures will be fitted into reconstruction of the contracted baseplate. Our results provide first structural characterisation of contractile phage infecting a Gram-positive bacterium. Comparison of the two distinct baseplate states will allow us to describe molecular mechanism of initial stage of phage infection in detail. |
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