Simulation systems.

aDomain structures used to start the simulations; includes also the linker chain covalently connecting the domains.bThe simulations where no force was applied were used to study the flexibility of the domains at room temperature and determine persistent inter-domain contacts.cAll three simulations with the FimH domains were started from the X-ray structure, but different velocities were assigned to the atoms at the beginning of each run.dThe pulling runs with the fimbrial tip were started from the conformation obtained after equilibrating the structure at 300 K during 3 ns.