Bacteriophage Host Interaction in Lactic Acid Bacteria
Christina Skovgaard Vegge, John Gerald Kenny, Lone Brøndsted, Stephen Mc Grath, and Douwe van Sinderen
from: Bacteriophage: Genetics and Molecular Biology (Edited by: Stephen Mc Grath and Douwe van Sinderen). Caister Academic Press, U.K. (2007)
The first contact between an infecting phage and its bacterial host is the attachment of the phage to the host cell. This attachment is mediated by the phage's receptor binding protein (RBP), which recognizes and binds to a receptor on the bacterial surface. RBP's are also referred to as: host specificity protein, host determinant, and anti-receptor. For simplicity, the RBP term will be used here. A variety of molecules have been suggested to act as host receptors for bacteriophages infecting lactic acid bacteria (LAB); among those are polysaccharides, (lipo)teichoic acids as well as a single membrane protein. A number of RBPs of LAB phages have been identified by the generation of hybrid phages with altered host range. These studies, however, also found additional phage proteins to be important for successful a phage infection. Analysis of the crystal structure of several RBPs indicated that these proteins share a common tertiary folding as well as supporting previous indications of the saccharide nature of the host receptor. The Gram-positive LAB have a thick peptidoglycan layer, which must be traversed in order to inject the phage genome into the bacterial cytoplasm. Peptidoglycan-degrading enzymes are expected to facilitate this penetration and such enzymes have been found as structural elements of a number of LAB phages read more ...