Crowding effect on helix-coil transition: beyond entropic stabilization

Details Crowding effect on helix-coil transition: beyond entropic stabilization Crowding effect on helix-coil transition: beyond entropic stabilization

2011-12-20

arxiv.org/abs/1112.4676v1

Physics

Condensed Matter

Soft Condensed Matter

Scientific paper

We report circular dichroism measurements on the helix-coil transition of poly(L-glutamic acid) in solution with polyethylene glycol (PEG) as a crowding agent. Using small angle neutron scattering, PEG solutions have been characterized and found to be well described by the picture of a transient network of mesh size $\xi$, usual for semi-diluted chains in good solvent. We show that the increase of PEG concentration stabilizes the helices and increases the transition temperature. But more unexpectedly we also notice that the increase of crowding agent concentration reduces the mean helix extent at the transition, or in other words reduces its cooperative feature. This result cannot be accounted for by an entropic stabilization mechanism. Comparing the mean length of helices at the transition and the mesh size of the PEG network, our results strongly suggest two regimes: helices shorter or longer than the mesh size.

Affiliated with

Also associated with

No associations

Rating

Crowding effect on helix-coil transition: beyond entropic stabilization does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Crowding effect on helix-coil transition: beyond entropic stabilization, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Crowding effect on helix-coil transition: beyond entropic stabilization will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-56291