11MF
Cryo-EM of T2SS PulG pilus
Summary for 11MF
| Entry DOI | 10.2210/pdb11mf/pdb |
| EMDB information | 75833 |
| Descriptor | Type II secretion system core protein G, CALCIUM ION (2 entities in total) |
| Functional Keywords | endopilus, t2ss, pulg, protein fibril |
| Biological source | Klebsiella oxytoca |
| Total number of polymer chains | 4 |
| Total formula weight | 56964.14 |
| Authors | Sonani, R.R.,Lejeune, M.,Ivashchenko, S.,Bardiaux, B.,Vos, M.,Francetic, O.,Shevchik, V.E.,Izadi-Pruneyre, N.,Egelman, E.H. (deposition date: 2026-03-04, release date: 2026-09-23) |
| Primary citation | Lejeune, M.,Ivashchenko, S.,Dazzoni, R.,Bardiaux, B.,Sonani, R.R.,Vos, M.,Jacobsen, T.,Egelman, E.H.,Nilges, M.,Francetic, O.,Shevchik, V.E.,Izadi-Pruneyre, N. Structural determinants of endopilus assembly, stability, and functional specificity in bacterial type II secretion. Structure, 2026 Cited by PubMed Abstract: Gram-negative bacteria employ the type II secretion system (T2SS) to transport folded protein effectors via a periplasmic helical polymer called the endopilus, composed of one major and four minor pilin subunits. Endopili resemble type IV pili but feature a conserved calcium-binding site stabilizing their major pilins. Endopilus polymerization is coupled to substrate translocation through a dedicated outer membrane channel. We compared T2SSs from plant and human pathogens, Dickeya dadantii and Klebsiella oxytoca, respectively. Despite different ecological niches and secreted effectors, their major pilins (OutG and PulG) share >77% sequence identity. Using NMR and cryo-EM, we solved structures of calcium-bound OutG monomer, as well as OutG and PulG endopili at 3.6 Å resolution. Combining structural, mutational, and biophysical analyses with in vivo assays, we identified key determinants of secretion specificity and endopilus stability. Our findings reveal how minor sequence variations in conserved nanomachines drive functional adaptation to diverse environments. PubMed: 42624105DOI: 10.1016/j.str.2026.07.013 PDB entries with the same primary citation |
| Experimental method | ELECTRON MICROSCOPY (3.6 Å) |
Structure validation
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