DOI: 10.1101/497933Dec 16, 2018Paper

Motor properties of PilT-independent type 4 pilus retraction in gonococci

BioRxiv : the Preprint Server for Biology
Robert ZöllnerBerenike Maier


Bacterial type 4 pili (T4P) belong to the strongest molecular machines. The gonococcal T4P retraction ATPase PilT supports forces exceeding 100 pN during T4P retraction. Here, we address the question whether gonococcal T4P retract in the absence of PilT. We show that pilT deletion strains indeed retract their T4P but the maximum force is reduced to 5 pN. Similarly, the speed of T4P retraction is lower by orders of magnitude compared to T4P retraction driven by PilT. Deleting the pilT paralogues pilU and pilT2 in the DpilT background did not inhibit T4P retraction, indicating that the PilT-like proteins do not compensate for PilT. Furthermore, we show that depletion of proton motive force did not inhibit pilT-independent T4P retraction. We conclude that the retraction ATPase is not essential for gonococcal T4P retraction. However, the force generated in the absence of PilT is too low to support important functions of T4P including twitching motility, fluidization of colonies, or induction of host cell response.

Related Concepts

Gene Deletion
Bacterial Fimbria
Pili, bacterial receptor
Fimbriae Proteins
Proton-Motive Force
Fimbriae receptor, type 1
Pilus Assembly
Cell-mediated Immune Response
Pilus Retraction
ING2 protein, human

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