Seeing the Unseen with Single-Molecule Perspective
Tae-Young Yoon PH.D
1National Creative Research Initiative Center for Single-Molecule Systems Biology,
2Samsung Science and Technology Foundation and 3Department of Physics
KAIST, Daejeon 305-701, Korea
Handling molecules one at a time and measuring signals from the single molecules provides a unique opportunity to address fundamental biological problems. In this seminar, I will talk about our two recent experiments that cannot be paralleled in conventional bulk measurements. First, by combining two orthogonal techniques of single-molecule FRET and magnetic tweezers, we reveal how the 20S particle consisting of NSF and a-SNAP disassembles single SNARE complexes [1-3]. We observed that NSF exploits only one round of ATP binding and hydrolysis to disassemble the SNARE complex, one of the most stable protein complexes, suggesting an incredibly high mechanical efficiency of NSF compared to other AAA+ ATPases. Second, by employing real-time single-molecule fluorescence imaging as a detection scheme, we have recently demonstrated a single-molecule version of the co-immunoprecipitation (co-IP) analysis, which provides an improvement of five orders of magnitude in the time resolution [4,5]. With the single-molecule sensitivity and millisecond time resolution, it is possible to detect changes in the protein-protein interactions in a given tumour tissue. This will shed light onto the molecular lesions that drive individual cancers at the level of protein-protein interactions. I will close the talk with brief outlook for future researches.
[1] H.-K. Lee et al., “Dynamic Ca2+-Dependent Stimulation of Vesicle Fusion by Membrane-Anchored Synaptotagmin 1”, Science 328, 760 (2010).
[2] D.-Y. Min et al., “Mechanical unzipping and rezipping of a single SNARE complex reveals large hysteresis as a force-generating mechanism”, Nat. Comm. 4, 1705 (2013).
[3] J.-K. Ryu et al., “NSF disassembles a single SNARE complex in one round of ATP turnover”, submitted.
[4] H.-W. Lee et al., “Real-time single-molecule co-immunoprecipitation analyses reveal cancer-specific Ras signaling dynamics”, Nat. Comm. 4, 1505 (2013)
[5] H.-W. Lee et al., “Real-time single-molecule co-immunoprecipitation of weak protein-protein interactions”, Nat. Protoc. 8, 2405 (2013).
Venue: Room143,New Biology Building,THU
Time: Oct 08(wednesday),2014;10:00
Host: Prof.Hongwei Wang
举办单位：生命科学联合中心
