콜럼비아대학교의 이자일 박사님을 초청하여 아래와 같이 특별 세미나를 개최합니다.

학과 구성원 여러분의 많은 참석을 부탁 드립니다. 

         아             래  

     1. 일시: 2013년 4월 30일(화) 오후 4시 30분 

     2. 장소: 제1과학관 기초과학연구소세미나실 31317호

     3. 연사: 이  자  일  박사님 (Columbia University) 

     4. 제목: DC (DNA Curtains) and AC (Actin Curtains) in single-molecule biophysics

     5. 초록: Single-molecule biophysics provides powerful tools for investigating in-depth biological phenomena that cannot be uncovered by conventional biophysical and biochemical methods. A variety of single-molecule methods have been developed and are rapidly expanding their realms. Here I introduce two novel single-molecule techniques, DNA curtains (DC) and actin curtains (AC), both of which provide in vitro platforms to study biopolymers and associated proteins based on the integration of lipid bilayer fluidity, microfluidics, total internal reflection fluorescence microscopy (TIRFM), and nano-technology. The advantages of these techniques are 1) visualizing individual bio-molecules in real time, 2) observing hundreds of bio-molecules within one field-of-view, which are responsible for the statistical reliability, and 3) offering a bio-compatible environment through the membrane bilayer. With the help of DNA curtains the activities of FtsK are examined, which is a DNA translocase moving along double-stranded DNA. The DNA curtains assay demonstrates that FtsK is assembled on a specific DNA sequence, translocates along DNA rapidly and processively, and displaces protein roadblocks during translocation. The results give an insight into the biological function of FtsK in the E. coli cell division and chromosome segregation. On the other hand, the actin curtains technique enables one to characterize actin filament growth by a formin, which enhances actin nucleation. Moreover, under the hydrodynamic flow, the polymerization of actin filaments increases force applied to the formins. This allows one to examine the force effect on the formin-mediated actin polymerization. Surprisingly, the force reduces the formin-mediated actin polymerization rate without any cofactor, whereas the polymerization rate is increased by force in the presence of a cofactor, profilin.