Even though this salt bridge is in the least well-defined map region near the tip of the long β-hairpins, there was significant density for it, as shown in the new panel G of Figure 5. We would like to point out that we did not look for this salt bridge, but deduced that there had to be one in this position from our chain trace, and then found the corresponding map density, which again shows there were no chain tracing errors in the β-barrel. Moreover, the interaction of adjacent β-hairpins that includes this salt bridge is in excellent agreement with the S-S crosslinking studies of Tweten and colleagues in the related PFO (Sato et al. 2013, NatChemBiol). This is now explained more fully in subsection “CryoEM structure of the PLY pore complex” paragraph four of the revised manuscript.