Unfolding Under Shear

What does it happen to a protein in fluid shear flow? According to some studies, a protein could be forced to unfold. However there is not agreement on the necessary strength, or more technically, on the magnitude of the shear rate that could cause the unfolding to happen. Jaspe and Hagen for example estimated that only an extraordinary value of the shear rate (10⁷ s^-1) is effective for unfolding globular proteins, read their work in Biophys. J.(2006)  here.

In our group we have recently combined an effective coarse-grained model for simulating protein motion with an engine for considering hydrodynamic interactions. A first glance to this coupling is presented in a recent review in ChemSocRev(2014), see here. We also presented the preliminary results of an investigation aimed to understand how shear flow acts on the stability of proteins. We actually show the unfolding process of a simple β-hairpin peptide under laminar shear flow. We have used a very strong shear rate, 10¹⁰s^-1, and the unfolding occurs in about 10 ns. We are now checking how the unfolding rate changes by decreasing the shear rate.

Fig.9 in Sterpone et al, Chem.Soc.Rev. (2014) DOI:10.1039/C4CS00048J.  Unfolding of β-hairpin under shear.