Force generation by bacterial type IV pili

Lena Dewenter, Claudia Meel



Laser tweezers with force-feedback in combination with tools from statistical physics enable us to measure the force generated by a single pilus motor in a living bacterium.



Type IV pili are among the most wide-spread bacterial surface appendages. They are multifunctional polymers that mediate adhesion, motility, biofilm formation, and horizontal gene transfer. By depolymerization, type IV pili generate very high forces, exceeding 150 pN. We have developed biophysical tools for characterizing the dynamics and force generation of single pili. Currently, we are investigating the molecular mechanism of high force generation. This project involves joint forces from molecular biology and nanotechnology. Using genetic tools, we design bacterial mutant strains which we hypothesize to have altered proficiency in force generation. In a continuous effort, we improve our laser tweezers system for characterizing force generation and dynamics of these mutant strains in living cells at the single molecule level.

Main collaborators:
Michael Koomey, Oslo

Review articles:

Maier, B., Wong, G.C.L., How bacteria use type IV pilus machinery on surfaces,  Trends Microbiol., 23(12), 775 (2015)
Maier, B. The type IV pilus system - a tunable molecular motor,  Soft Matter, 9, 5667 - 5671 (2013)
Maier, B. Using laser tweezers to measure twitching motility.  Curr. Opin. Microbiol. 8(3), 1-6 (2005)