Title: Size-dependent forced PEG partitioning into channels: VDAC, OmpC, and α-hemolysin

Abstract

Nonideal polymer mixtures of PEGs of different molecular weights partition differently into nanosize protein channels. Here, we assess the validity of the recently proposed theoretical approach of forced partitioning for three structurally different beta-barrel channels: voltage-dependent anion channel from outer mitochondrial membrane VDAC, bacterial porin OmpC (outer membrane protein C), and bacterial channel-forming toxin alpha-hemolysin. Our interpretation is based on the idea that relatively less-penetrating polymers push the more easily penetrating ones into nanosize channels in excess of their bath concentration. Comparison of the theory with experiments is excellent for VDAC. Polymer partitioning data for the other two channels are consistent with theory if additional assumptions regarding the energy penalty of pore penetration are included. In conclusion, the obtained results demonstrate that the general concept of "polymers pushing polymers" is helpful in understanding and quantification of concrete examples of size-dependent forced partitioning of polymers into protein nanopores.

Authors:

Aksoyoglu, M. Alphan ^[1]; Podgornik, Rudolf ^[2]; Bezrukov, Sergey M. ^[3]; Gurnev, Philip A. ^[4]; Muthukumar, Murugappan ^[5]; Parsegian, V. Adrian ^[1]

---

+ Show Author Affiliations

1. Department of Physics, University of Massachusetts, Amherst, MA 01003,
2. Department of Physics, University of Massachusetts, Amherst, MA 01003,, Department of Physics, Faculty of Mathematics and Physics, University of Ljubljana, 1000 Ljubljana, Slovenia,, Department of Theoretical Physics, J. Stefan Institute, 1000 Ljubljana, Slovenia,
3. Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892,
4. Department of Physics, University of Massachusetts, Amherst, MA 01003,, Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892,
5. Department of Polymer Science and Engineering, University of Massachusetts, Amherst, MA 01003

Publication Date:

Wed Jul 27 00:00:00 EDT 2016

Research Org.:

Univ. of Massachusetts, Amherst, MA (United States)

Sponsoring Org.:

USDOE; USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division

OSTI Identifier:

1274822

Alternate Identifier(s):

OSTI ID: 1439277

Grant/Contract Number:  

SC0008176

Resource Type:

Published Article

Journal Name:

Proceedings of the National Academy of Sciences of the United States of America

Additional Journal Information:

Journal Name: Proceedings of the National Academy of Sciences of the United States of America Journal Volume: 113 Journal Issue: 32; Journal ID: ISSN 0027-8424

Publisher:

Proceedings of the National Academy of Sciences

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE; β-barrel pores; nanopore-based sensing; polymer confinement; polymer; transport; macromolecular crowding