Figure 2. Identification and characterization of ICP1’s holin TeaA.

(A) Schematic of canonical T4 lysis in E. coli. Lysis occurs in four steps with a potential delay caused by lysis inhibition. Step one: Phage encoded proteins including holins, endolysins, and spanins accumulate in the cell. In the event of superinfection, antiholins halt the lysis program causing lysis inhibition (LIN). Step two: Holins are triggered collapsing the proton motive force and forming holes in the inner membrane (IM) releasing endolysins to the periplasm. Step three: The peptidoglycan (PG) is degraded by endolysins. Step four: Spanins fuse the inner and outer membrane (OM). (B) Transmembrane domains (grey bars) were predicted in three gene products (gp) in a conserved locus of ICP1. (C) Relative state of the proton motive force as measured by the ratio of red to green arbitrary fluorescence units (AFU) from DiOC₂(3) after ectopic gene expression. Points represent individual replicates; bar height is the average; error bars display the standard deviation of samples. Significance was calculated via one-way ANOVA followed by Dunnett’s test. ****p≤0.0001; **p≤0.01. (D) Chemical triggering with 2,4-dinitrophenol (arrow) after ectopic gene expression as measured by optical density (OD₆₀₀). Points show the average of four replicates; shading shows the standard deviation.