PT  - JOURNAL ARTICLE
AU  - Nita R. Shah
AU  - Tomas B. Voisin
AU  - Edward S. Parsons
AU  - Courtney M. Boyd
AU  - Bart W. Hoogenboom
AU  - Doryen Bubeck
TI  - Structural basis for tuning activity and membrane specificity of bacterial cytolysins
AID  - 10.1101/2020.06.16.154724
DP  - 2020 Jan 01
TA  - bioRxiv
PG  - 2020.06.16.154724
4099  - http://biorxiv.org/content/early/2020/06/17/2020.06.16.154724.short
4100  - http://biorxiv.org/content/early/2020/06/17/2020.06.16.154724.full
AB  - Cholesterol-dependent cytolysins (CDCs) form protein nanopores to lyse cells. They target eukaryotic cells using different mechanisms, but all require the presence of cholesterol to pierce lipid bilayers. How CDCs use cholesterol to selectively lyse cells is essential for understanding virulence strategies of several pathogenic bacteria, and for repurposing CDCs to kill new cellular targets. Here we address that question by trapping an early state of pore formation for the CDC intermedilysin, bound to the human immune receptor CD59 in a nanodisc model membrane. Our cryo-electron microscopy map reveals structural transitions required for oligomerization, which include the lateral movement of a key amphipathic helix. We demonstrate that the charge of this helix is crucial for tuning lytic activity of CDCs. Furthermore, we discover modifications that overcome the requirement of cholesterol for membrane rupture, which will facilitate engineering the target-cell specificity of pore-forming proteins.Competing Interest StatementThe authors have declared no competing interest.