Single Molecule Probing of Dynamic Conformation, Molecular Interactions and Dynamic Localizations In-vitro, in Live Cells and in Organisms

Wednesday, September 19, 2007 - 1:30pm - 2:30pm
EE/CS 3-180
Shimon Weiss (University of California, Los Angeles)
We applied single molecule spectroscopy using alternating laser
excitation (ALEX) to the study of transcription initiation by e-coli RNA
polymerase. We find that the transcription factor sigma70 is not
obligatorily released in the transition from initiation to elongation
and that the mechanism for abortive initiation is governed by DNA

We also applied ALEX spectroscopy to the study the polymer properties of
single-stranded DNA and double-stranded DNA, and to protein folding. We
find that the collapsed state of protein L is not driven by native
contacts, and we show that Acyl-CoA binding protein (ACBP) has a
residual structure in the denatured state.
Lastly, we demonstrate the use of peptide-coated quantum dots for the
study of lipid rafts in live cells' membranes and for molecular imaging
in living cells and small organisms.