Rockford Draper, Ph.D.
B.A., Chemistry, University of Washington
Ph.D., Biological Chemistry, University of California, Los Angeles
Member, American Association for the Advancement of Science
Member, American Society for Cell Biology
Dr. Draper’s research interests are the molecular mechanisms of membrane trafficking in eukaryotic cells and applications of molecular and cell biology to the emerging field of bionanotechnology. Biology projects currently underway include the use small interfering RNA (siRNA) fragments to suppress proteins involved in membrane traffic and the study of coat protein that function in the Golgi complex. Bionanotechnology projects include interfacing proteins with carbon nanotubes and the use of nanoelectrodes to study neural function.
Two challenges for effectively exploiting the remarkable properties of single-walled carbon nanotubes (SWNTs) are the isolation of intact individual nanotubes from the raw material and the assembly of these isolated SWNTs into useful structures. In this study, we present atomic force microscopy (AFM) evidence that we can isolate individual peptide-wrapped SWNTs, possibly connected end-to-end into long fibrillar structures, using an amphiphilic alpha-helical peptide, termed nano-1.
Transmission electron microscopy (TEM) and well-resolved absorption spectral features further corroborate nano-1's ability to debundle SWNTs in aqueous solution. Peptide-assisted assembly of SWNT structures, specifically in the form of Y-, X-, and intraloop junctions, was observed in the AFM and TEM images.
Figure 1: Computer-based model of a carbon nanotube surrounded by six amphiphilic peptide helices
Left: End view of a slice through a nanotube (purple ring in center) wrapped by six helices (red coils). The slice is seven residues thick (one heptad of each helix). Val and Phe residues shown as ball-and-stick in green to demonstrate contact of the hydrophobic face of the helix with the surface of the nanotube. Other residues are dark lines.
Center: Side view of the backbone of each helix represented by ribbons (no sidechains of helix shown).
Right: View down the long axis of an aggregate of seven peptide-wrapped nanotubes. The nanotubes are purple, the hydrophobic faces of the peptides are green, and the polar surfaces of the peptides are black. Note the interaction of residues from the polar surfaces of peptides that wrap different nanotubes.
Models generated by Dr. Gregg Dieckmann, UTD Chemistry Department
- Zorbas, V.; Ortiz-Acevedo, A.; Dalton, A.B.; Yoshida, M.M.; Dieckmann, G.R.; Draper, R.K.; Baughman, R.H.; Yacaman, M.J.; Musselman, I.H. “Preparation and Characterization of Individual Peptide-Wrapped Single-Walled Carbon Nanotubes”, J. Am. Chem. Soc. (2004) 126: 7222-7227.
- Chen, A., R.J. AbuJarour and R.K. Draper. 2003. Evidence that the transport of ricin to the cytoplasm is independent of both Rab6A and COPI. Journal of Cell Science. 116:3503-3510.
- Dieckmann, G.R., A.B. Dalton, P.A. Johnson, J. Razal, J. Chen, G.M. Giordano, E. Munoz, I.H. Musselman, R.H. Baughman and R.K Draper. 2003. Controlled Assembly of Carbon Nanotubes by Designed Amphiphilic Peptide Helices. J. Am. Chem. Soc. 125:1770-1777.
- Dalton, A.B., A. Ortiz-Acevedo, V. Zorbas, W.M. Sampson, S. Collins, J. Razal, M.M. Yoshida, R.H. Baughman, R.K. Draper, I.H. Musselman, M.J. Yacaman and G.R. Dieckmann. 2004. Hierachial Self-Assemby of Peptide-Coated Carbon Nanotubes. In press.
- Updated: February 6, 2006