Infection caused by antibiotic-resistant S. aureus strains are difficult to treat and can induce life-threatening symptoms. Because of the slow development of new antibiotics, alternative treatments are being looked for. One of the promising approaches is phage therapy employing bacterial viruses (phages) [1, 2]. Phage phi812K1/420 from the family Myoviridae infects and kills S. aureus cells [3]. The phage can infect 95 % of S. aureus strains, including those resistant to antibiotics. Such a wide host range makes the phage phi812K1/420 a promising agent for phage therapy.
Receptor Binding Protein 1 (RBP1) is located in the baseplate of the phage phi812K1/420 [4]. At the onset of infection, RBP1 binds to specific receptor at the surface of S. aureus and enables attachment of the phage to the bacterial surface. The goal of this project is to determine the RBP1 structure using X-ray crystallography and cryo-electron microscopy. Key interactions of RBP1 with S. aureus cell wall receptors will be studied with biochemical and biophysical assays, such as glycan array or difference scanning fluorimetry. RBP1 characterization will help to complete our understanding of the phage infection process and allow design of phi812 variants targeted against specific S. aureus strains.