Baseplate structure of bacteriophage phi812 and mechanism of cell binding and degradation
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| Year of publication | 2021 |
| Type | Conference abstract |
| MU Faculty or unit | |
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| 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 S. aureus isolates 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. The reconstruction of the center of native baseplate reaches resolution of 4 A, which enables us to build individual protein structures. Also, selected proteins involved in host cell wall binding and penetration 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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