holinendolysins

Holinendolysins are a class of bacteriophage lysis proteins. They are involved in the final stage of the phage replication cycle, known as cell lysis. Holinendolysins are typically composed of two functional components: holins and endolysins. Holins are membrane-spanning proteins that accumulate in the phage-infected bacterial cell's cytoplasmic membrane. At a specific time, often triggered by an internal phage-encoded signal, the holins form pores in the membrane. This pore formation disrupts the membrane integrity, creating a pathway for the second component, the endolysins, to access the bacterial peptidoglycan layer. Endolysins are peptidoglycan hydrolases, meaning they break down the bacterial cell wall. Once released by the holin-mediated membrane permeabilization, the endolysins degrade the peptidoglycan from the outside of the cell. This enzymatic destruction of the cell wall leads to the rupture of the bacterium and the release of newly assembled phage particles, allowing them to infect new host cells. The coordinated action of holins and endolysins is essential for efficient phage propagation and is a target for developing phage-based antibacterial therapies.