COLL 13 |
| Helen G. Hansma1, Roxana Golan2, Eduard Mateescu1, Rachel Steinberger3, Patricia A. Holden3, and Emin Oroudjev1. (1) Department of Physics, University of California, Santa Barbara, CA 93106, (2) Dept. of Chemical Engineering, Ben-Gurion University of the Negev, Beer Sheva, Israel, (3) Bren School of Environmental Science & Management, University of California, Santa Barbara, CA 93106 |
| Atomic Force Microscopy (AFM) and Molecular Pulling (Force Spectroscopy) both interact with surfaces. The surfaces of membranes and macromolecular structures occupy much of the volume of living organisms and provide the ‘platforms’ upon which many of life’s processes occur. The time is long past when cells were viewed as bags of cytoplasm. Thus it is appropriate that new methodologies such as AFM are designed to investigate biomaterials on surfaces, as opposed to biomaterials in solution. This talk will present recent work from the authors’ lab on bacterial biofilms, spider silk, and DNA. Bacterial biofilms are a natural biological surface that has been probed by AFM to characterize bacterial size and surface morphology under varying nutrient conditions (Auerbach, et al., J. Bacteriol. 182, 3809-3815 (2000); Steinberger, et al., Microbial Ecology 43, 416-423 (2002)). AFM and Molecular Pulling on a bioengineered spider dragline-silk protein have generated models for the intramolecular folding and multi-molecular assembly of silk nanofibers (Oroudjev et al., Proc. Natl. Acad. Sci. USA 99, 6460-6465 (2002)). Novel results from AFM of DNA have revealed toroid composition of DNA condensed for gene therapy (Golan, et al., Biochemistry 38, 14069-14076 (1999)) and a sequence-dependent DNA condensation (Sitko, et al., Biophysical Journal, in press (2002)) that is consistent with the electrostatic zipper theory (Kornyshev & Leikin, Physical Review Letters 82, 4138-41 (1999)). This research was supported by NSF MCB. |
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Nanoscale Imaging of Biological Systems
Division of Colloid and Surface Chemistry |