Single-protein force spectroscopy: Sequence dependence
Max-Planck-Institut für Polymerforschung -
55128 Mainz, Germany
Accepted: 21 December 2001
We study the elastic properties of a single A/B copolymer chain with a specific sequence. We predict a rich structure in the force-extension relations which can be addressed to the sequence. The variational method is introduced to probe local minima on the path of stretching and releasing. 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.
PACS: 36.20.Fz – Constitution (chains and sequences) / 87.15.Nn – Properties of solutions; aggregation and crystallization of macromolecules / 83.85.Cg – Rheological measurements - rheometry
© EDP Sciences, 2002