Many cells are protected by a network of polysaccharides called glycocalyx. The glycocalyx (400 nm or more) layer protects the cell from hostile environments, and prevents viruses from reaching their entry receptor at the cell surface .
Bacterial viruses infecting encapsulated cell carry an exopolysaccharide (EPS) degrading enzymes as tailspike proteins in order to digest this sugar coat and reach the outer membrane or the peptidoglycan layer . The capsule can be composed of various EPS such as alginates, polysialic acids (PSAs), and hyaluronic acid (HA).
Virus | Family | Host bacteria | Surface component type | Phage degrading enzyme | ref. |
Phage φ92 | Myoviridae | E.coli (K1, K5, K92), Salmonella strains | PSA, capsular | Endosialidase gp143 | |
Phage K1A | Podoviridae | Escherichia coli | PSA, capsular | Endosialidase | |
Phage K1E | Podoviridae | Escherichia coli | PSA, capsular | Endosialidase | |
Phage K1F | Podoviridae | Escherichia coli | PSA, capsular | Endosialidase | |
Phage 63D | Siphoviridae | - | PSA, capsular | Endosialidase | |
Phage K1-5 | Podoviridae | Escherichia coli | PSA, capsular | Endosialidase | |
Phage CUS-3 | Podoviridae | Escherichia coli | PSA, capsular | Endosialidase | |
Phage PT-6 | unclassified | Pseudomonas aeruginosa | Alginate, capsular | Alginate lyase | |
Phage H4489A | unclassified | Streptococcus pyogenes | HA, capsular | Hyaluronidase | |
Phage 370.1 | Siphoviridae | Streptococcus pyogenes | HA, capsular | HylP1, HylP2, HylP3 | |
Phage H10403 | unclassified | Streptococcus pyogenes | HA, capsular | Hyalurono- glucosaminidase | |
Phage AF | Podoviridae | Pseudomonas putida | EPS, capsular | EPS hydrolase |