Diblock copolymers enhance folding of a mechanosensitive membrane protein during cell-free expression

Miranda L. Jacobs, Margrethe A. Boyd, Neha P. Kamat*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

20 Scopus citations

Abstract

The expression and integration of membrane proteins into vesicle membranes is a critical step in the design of cell-mimetic biosensors, bioreactors, and artificial cells. While membrane proteins have been integrated into a variety of nonnatural membranes, the effects of the chemical and physical properties of these vesicle membranes on protein behavior remain largely unknown. Nonnatural amphiphiles, such as diblock copolymers, provide an interface that can be synthetically controlled to better investigate this relationship. Here, we focus on the initial step in a membrane protein’s life cycle: expression and folding. We observe improvements in both the folding and overall production of a model mechanosensitive channel protein, the mechanosensitive channel of large conductance, during cell-free reactions when vesicles containing diblock copolymers are present. By systematically tuning the membrane composition of vesicles through incorporation of a poly(ethylene oxide)-b-poly (butadiene) diblock copolymer, we show that membrane protein folding and production can be improved over that observed in traditional lipid vesicles. We then reproduce this effect with an alternate membrane-elasticizing molecule, C 12 E 8 . Our results suggest that global membrane physical properties, specifically available membrane surface area and the membrane area expansion modulus, significantly influence the folding and yield of a membrane protein. Furthermore, our results set the stage for explorations into how nonnatural membrane amphiphiles can be used to both study and enhance the production of biological membrane proteins.

Original languageEnglish (US)
Pages (from-to)4031-4036
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume116
Issue number10
DOIs
StatePublished - 2019

Keywords

  • Cell-free protein
  • Diblock copolymer
  • Elastic modulus
  • Membrane protein folding
  • Synthesis | vesicles

ASJC Scopus subject areas

  • General

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