https://doi.org/10.1140/epjb/e2002-00248-0
Single chain force spectroscopy - Reading the sequence of HP protein models
Max-Planck-Institut für Polymerforschung,
Ackermannweg 10, 55128 Mainz, Germany
Corresponding author: a lee@mpip-mainz.mpg.de
Received:
5
March
2002
Revised:
16
May
2002
Published online:
13
August
2002
We study the elastic properties of single A/B random copolymer chains, with a specific sequence and use them as theoretical model for so called HP proteins. HP proteins carry hydrophilic (P) and hydrophobic (H) monomers. We predict a rich structure in the force-extension relations which can be attributed to the information in the sequence. The variational method is used to probe local minima on the path of stretching and releasing for the chain molecules. At a given force, we find multiple configurations which are separated by energy barriers. A collapsed globular configuration consists of several domains which unravel cooperatively. Upon stretching, the unfolding path shows a stepwise pattern corresponding to the unfolding of each domain. While releasing, several cores can be created simultaneously in the middle of the chain, resulting in a different path of collapse. The long-range interactions and stiffness of the chain simplify the potential landscape given by the disorder in sequence.
PACS: 36.20.Fz – Constitution (chains and sequences) / 87.15.Da – Physical chemistry of solutions of biomolecules; condensed states / 87.15.-v – Molecular biophysics
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2002