Direct quantitation of peptide-mediated protein transport across a droplet-interface bilayer.

We introduce a new method for monitoring and quantitating the transport of materials across a model cell membrane. As a proof-of-concept, the cell-penetrating peptide, Pep-1, was used to carry horseradish peroxidase (HRP) across droplet-interface bilayers (DIBs). Two submicroliter, lipid-encased aqueous droplets form a membrane at the contacting interface, through which enzyme-peptide complexes pass during transport. Following transport, the droplets are separated and the captured enzymes are assayed by a fluorogenic reaction. The DIB method recapitulates the findings of earlier studies involving Pep-1, including the dependence of protein transport on voltage and membrane charge, while also contributing new insights. Specifically, we found that leaflet charge symmetry may play a role in Pep-1-mediated protein translocation. We anticipate that the DIB method may be useful for a variety of transport-based studies.

Citation

Jing Huang, Max Lein, Christopher Gunderson, Matthew A Holden. Direct quantitation of peptide-mediated protein transport across a droplet-interface bilayer. Journal of the American Chemical Society. 2011 Oct 12;133(40):15818-21

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PMID: 21838329

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