  Molecular transport of biomolecules plays a pivotal role in the machinery of
life. Yet, this role is poorly understood due the lack of quantitative
information. Here, the role and properties of the C-terminal region of
Escherichia coli Hfq is reported, involved in controlling the flow of a DNA
solution. A combination of experimental methodologies has been used to probe
the interaction of Hfq with DNA and to measure the rheological properties of
the complex. A physical gel with a temperature reversible elasticity modulus is
formed due to formation of non-covalent crosslinks. The mechanical response of
the complexes shows that they are inhomogeneous soft solids. Our experiments
indicate that Hfq C-terminal region could contribute to genome mechanical
response. The reported viscoelasticity of the DNA-protein complex might have
implications for cellular pro-cesses involving molecular transport of DNA or
segments thereof.
