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

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.
 [1] ;  [2] ;  [3] ;  [4] ;  [1] ;  [1]
  1. Univ. of Massachusetts, Amherst, MA (United States)
  2. Univ. of Massachusetts, Amherst, MA (United States); Univ. of Ljubljana, Ljubljana (Slovenia); J. Stefan Institute, Ljubljana (Slovenia)
  3. National Institutes of Health, Bethesda, MD (United States)
  4. Univ. of Massachusetts, Amherst, MA (United States); National Institutes of Health, Bethesda, MD (United States)
Publication Date:
Grant/Contract Number:
Published Article
Journal Name:
Proceedings of the National Academy of Sciences of the United States of America
Additional Journal Information:
Journal Volume: 113; Journal Issue: 32; Journal ID: ISSN 0027-8424
National Academy of Sciences, Washington, DC (United States)
Research Org:
Univ. of Massachusetts, Amherst, MA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division; USDOE
Country of Publication:
United States
36 MATERIALS SCIENCE; β-barrel pores; nanopore-based sensing; polymer confinement; polymer; transport; macromolecular crowding
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1439277