korean english


Home > 게시판 > 세미나

○ Date : 2015 10 15() 오후 4:30 ~ 5:30
○ Place : 
삼성학술도서관 7
Creative Learning Room
○ Speaker : Dr. Ja Yil Lee
이자일 박사 (콜럼비아 대학교, 미국
○ Topic : Single-Molecule Approach to Homology Search & Strand Exchange in Homologous Recombination


Homologous recombination (HR) is an important biological phenomenon because it repairs DNA double-strand break in an error-free way and rearranges genetic information during meiosis promoting genetic diversity. HR is mediated by the Rad51/RecA family of recombinases. The essential roles of the recombinases are searching for the homologous sequence and then exchanging DNA strands. Despite decades of work, the physical basis of the homology search and strand-exchange is not well-defined. Using the single-molecule DNA curtain technique, we find that 8-nt is the minimum size to search for homologous sequences and that the search process is accelerated by the facilitated exchange mechanism meaning by competitor-dependent dissociation. We also reveal that the strand exchange occurs in precise 3-nucleotide (nt) steps for prokaryotic RecA and eukaryotic Rad51 and Dmc1. The free energy difference between the steps is ~0.3 kBT, which is also conserved from bacteria to human. Molecular dynamics simulation suggests that Watson-Crick basepairing of base triplets is the molecular basis of the triplet stepping. Furthermore we show that all the recombinases can step over mismatched bases in the strand exchange. But only the meiosis-specific recombinase Dmc1 can step over mismatched bases without any destabilization of base-triplets, which enhances more genetic exchange during meiosis.

번호 제목 날짜 조회 수
공지 <12/8(Thu.) 11:00am>노벨상 소개 강연 - 2016년 노벨 물리학상: 위상 응집 물리의 탄생 2016.11.28 1060183
96 <Sep. 18(Fri.) 4:00 PM> Special seminar 2015.09.16 57955
95 학술세미나 개최 안내: Local Modes in Vibrational (and Rotational) Spectroscopy file 2015.10.01 55712
94 <Oct. 20(Tue.) 2:00 PM> High-throughput Synthesis of Oxide Thin Films 2015.10.05 127744
» <Oct.15(Thu) 16:30> Single-Molecule Approach to Homology Search & Strand Exchange in Homologous Recombination 2015.10.12 108689
92 <Oct.20(Tue) 16:00> Electromagnetic Response and Thermomagnetic Instabilities in Three-Dimensional Nanostructured Superconductors file 2015.10.15 94143
91 <Oct.20(Tue) 10:00-12:00> Novel quantum transport in Weyl semimetals and double-Weyl semimetals 2015.10.23 84689
90 <Nov.13(Fri) 16:00> Kondo screening in mixed valence and heavy fermion compounds and the signatures of Nozieres’ exhaustion 2015.11.04 122188
89 <Dec.30(Wed) 16:30> Some basics about the thermoelectricity; the semi-classical Boltzmann transport approach 2015.12.24 66981
88 <March 8(Tue) 18:00> Unsolved puzzles of Gamma-Ray Bursts 2016.03.03 67984
87 <March.18(Fri) 11:00> High Pressure Synthesis and Characterization of Non-Oxide Superconductors 2016.03.14 67670
86 <March.24(Thu) 14:00> A new boson and muon g-2 2016.03.17 65319
85 <4/6(Wed.) 1pm> Results from DM-Ice17 2016.04.05 78412
84 <April 25(Mon) 16:30> Neutron Recoil Polarization in Low‐energy Photodisintegration of the Deuteron 2016.04.25 53257
83 <May.27(Fri.) 10:00> Towards Magnetic 2D Materials 2016.04.27 80558
82 <6/24(Fri.) 1:30pm>Emergent geometry from field theory: Wilson's renormalization group revisited 2016.06.20 65779
81 <7/12(Tue.) 11:00> Spin-direction-dependent magnetoelastic coupling on MnO, CoO, and NiO file 2016.07.01 71935
80 <7/15(Fri.) 14:00> Electronic quasiparticles in the quantum dimer model 2016.07.12 68223
79 <7/15(Fri.) 11:00> Observation of a field induced quantum spin liquid in α-RuCl3 2016.07.14 63731
78 <7/18(Mon.) 14:00> GEANT4 Particle Physics Simulation Software: A Brief Overview From a User’s Perspective 2016.07.15 64754
77 <8/5(Fri.) 10:30> Phase Slips in Superfluid Spin Transport in Magnetic Wires 2016.08.02 55693