A. Suma, A. Rosa and C. Micheletti
Pore translocation of knotted polymer chains: how friction
depends on knot complexity
ACS Macro Letters, 2015, 4 , 1420-1424
Abstract, Link to online
article
Abstract
Knots can affect the capability of polymers to
translocate through narrow pores in complex and counter-
intuitive ways that are still relatively unexplored. We report here on a
systematic theoretical and computational investigation of the driven translocation of flexible chains
accommodating a large repertoire of knots trapped at the pore entrance.
These include composite knots, which are the most common
form of spontaneous entanglement in long polymers. Two
unexpected results emerge from this study. First, the high
force translocation compliance does not decrease
systematically with knot complexity. Second, the response of
composite knots is so dependent on the order of their factor
knots, that their hindrance can even be lower than some of
their prime components. We show that the resulting rich and
seemingly disparate phenomenology can be captured in a seamless framework
based on the mechanism by which the tractive force is propagated along and
past the knots. The quantitative scheme can be viably used for predictive
purposes and, hence, ought to be useful in applicative contexts, too.