1.제 목 : Dynamic self-assembly of biomacromolecules probed at the single
molecule and nanoscale level
2.연 사 : Joonil Seog Ph.D. (Professor, Department of Materials Science and Engineering,
Fischell Department of Bioengineering University of Maryland)
3.일 시 : 2011년 11월 24일 (목) 16:30-17:30
4.장 소 : 301동 1512-2호
5.내 용 : Single molecule studies have been very powerful in providing mechanistic insights on biomolecular machineries. The capability of monitoring time trajectories of a single molecule reveals not only the averaged properties from bulk ensemble measurements but also entire distribution of relevant properties with infrequent events. Using optical tweezers, unfolding and refolding process of cell adhesion molecule was studied at the single molecule level. The molecule exhibited stepwise multiple transitions in a specific order during unfolding processes, showing mechanical hierarchy in a single protein domain. In the force clamping experiment, three intermediate states were observed when the molecule hops between unfolded state and refolded state. The strong correlation between folding behavior and allosteric region was revealed. At the nanoscale level, dynamic self-assembly behaviors of silk-elastin-like protein (SELP) polymers were studied using atomic force microscopy. Peptide based nanofibers have great potential in building smart hierarchical structures due to their tunable structures at the single residue level and their ability to reconfigure themselves in response to environmental stimuli. We observed that pre-adsorbed silk-elastin-like protein polymers self-assemble into nanofibers through conformational changes on a mica substrate. Furthermore, we demonstrate that the rate of self-assembly was significantly enhanced by applying a nanomechanical stimulus using atomic force microscopy. The orientation of the newly grown nanofibers was mostly perpendicular to the scanning direction, implying that the new fiber assembly was locally activated with directional control. Our method provides a novel way to prepare nanofiber patterned substrates using a bottom-up approach.
6.약 력 :
Joonil Seog is a Assistant Professor of Materials Science and Engineering and Bioengineering at the University of Maryland in College Park. His research interests include single molecule mechanics and nanomechanics of biological materials using high resolution force spectroscopy. He received a B.S. and M.S. degree in Chemical Technology from Seoul National University. He came to the United States in 1997, and received a Sc.D. degree in polymer science and technology from Massachusetts Institute of Technology (with Professor Alan J. Grodzinsky and Christine Ortiz) in 2003. He continued his work at Immune Disease Institute in Harvard Medical School as a postdoctoral fellow with Timothy A. Springer. Dr. Seog joined the UMD faculty as an Assistant Professor in 2007. His current research focuses on understanding gene delivery mechanisms by cationic carriers, surface facilitated self-assembly of biopolymers, and dynamic folding behaviors of peptide based biomaterials. He is the recipient of NSF Career Award in 2011.
※ 문 의 : 기계항공공학부 전누리 교수 (880-7111)
