Molecular transport through channels and pores: Effects of in-channel interactions and blocking
Document Type
Article
Publication Date
8-1-2006
Abstract
Facilitated translocation of molecules through channels and pores is of fundamental importance for transmembrane transport in biological systems. Several such systems have specific binding sites inside the channel, but a clear understanding of how the interaction between channel and molecules affects the flow is still missing. We present a generic analytical treatment of the problem that relates molecular flow to the first passage time across and the number of particles inside the channel. Both quantities depend in different ways on the channel properties. For the idealized case of noninteracting molecules, we find an increased flow whenever there is a binding site in the channel, despite an increased first passage time. In the more realistic case that molecules may block the channel, we find an increase of flow only up to a certain threshold value of the binding strength and a dependence on the sign of the concentration gradient, i.e., asymmetric transport. The optimal binding strength in that case is analyzed. In all cases the reason for transport facilitation is an increased occupation probability of a particle inside the channel that overcomes any increase in the first passage time because of binding. © 2006 by The National Academy of Sciences of the USA.
Publication Title
Proceedings of the National Academy of Sciences of the United States of America
Recommended Citation
Bauer, W.,
&
Nadler, W.
(2006).
Molecular transport through channels and pores: Effects of in-channel interactions and blocking.
Proceedings of the National Academy of Sciences of the United States of America,
103(31), 11446-11451.
http://doi.org/10.1073/pnas.0601769103
Retrieved from: https://digitalcommons.mtu.edu/michigantech-p/9032