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New Biological Frontiers Illuminated by Molecular Sensors and Actuators
Poster Abstracts
7-POS
Board 7
Low-Noise, low-Capacitance Solid-State Nanopore Measurements at High Bandwidth for
Biomolecule Analysis
Chen-Chi Chien
, Adrian Balan, Rebecca Engelke, David Niedzwiecki, Marija Drndic.
University of Pennsylvania, Philadelphia, USA.
Solid-state nanopores are promising single molecule sensors, yet their applications are still
limited by relatively high noise and low bandwidth. We devised an integrated process to produce
silicon nitride (SiN) nanopore membranes suspended on glass substrates, thus successfully
lowering the chip capacitance. We obtain higher signal-to-noise ratios and better resolution in
ionic current signals than previously reported in solid state nanopores at megahertz bandwidth.
Specifically, we show measurements of ionic current during translocation of DNA molecules
through thin SiN membrane nanopores of small diameters at megahertz bandwidths with
enhanced ionic signal-to-noise ratios. We further discuss the potential of these results to pave the
way towards identifying intramolecular DNA sequences with solid-state nanopores, and how
these low capacitance glass chip devices could be used in other biomolecule sensing
applications.
8-POS
Board 8
Investigating the Coordination of Two ATPases in RecBCD Helicase Complex Using
Single-Molecule Fluorescence
Chia-Chuan Cho
, Hung-Wen Li.
National Taiwan University, Taipei, Taiwan.
RecBCD is an essential trimeric enzyme complex that initiates homologous recombinational
repair in E. coli. RecBCD complex contains single-stranded DNA nuclease and two DNA
helicases with single-stranded DNA translocase activities with opposite polarities. Previously,
we showed that RecB is a 3’-to-5’ single-stranded DNA translocase and RecD is a 5’-to-3’ one.
Here, we use total internal reflection fluorescence microscopy to observe and analyze individual
cy3-labeled ATP binding and turnover events during RecBCD unwinding at the single-molecule
level. This allows us to characterize both ATPase activities of RecB and RecD as well as the
coordination between both subunits.