Researchers are exploring whether these ubiquitous fluorinated molecules might worsen infections or hamper vaccine effectiveness.
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Edited by* David A. Tirrell, California Institute of Technology, Pasadena, CA, and approved June 5, 2012 (received for review April 3, 2012)
Abstract
Using recombinant amphiphilic proteins to self-assemble suprastructures would allow precise control over surfactant chemistry and the facile incorporation of biological functionality. We used cryo-TEM to confirm self-assembled structures from recombinantly produced mutants of the naturally occurring sunflower protein, oleosin. We studied the phase behavior of protein self-assembly as a function of solution ionic strength and protein hydrophilic fraction, observing nanometric fibers, sheets, and vesicles. Vesicle membrane thickness correlated with increasing hydrophilic fraction for a fixed hydrophobic domain length. The existence of a bilayer membrane was corroborated in giant vesicles through the localized encapsulation of hydrophobic Nile red and hydrophilic calcein. Circular dichroism revealed that changes in nanostructural morphology in this family of mutants was unrelated to changes in secondary structure. Ultimately, we envision the use of recombinant techniques to introduce novel functionality into these materials for biological applications.
Footnotes
- ↵1To whom correspondence should be addressed. E-mail: hammer{at}seas.upenn.edu.
Author contributions: K.B.V., R.P., and D.A.H. designed research; K.B.V. performed research; K.B.V. and R.P. contributed new reagents/analytic tools; K.B.V. and D.A.H. analyzed data; and K.B.V., R.P., and D.A.H. wrote the paper.
The authors declare no conflict of interest.
*This Direct Submission article had a prearranged editor.
This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1205426109/-/DCSupplemental.
Self-assembly of recombinant oleosin
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