DNA Translocation by Single-Molecule Studies
DNA translocation and looping mechanism of chromatin remodeling revealed by single-molecule studies
Dr. Yongli Zhang from Lawrence Berkeley National Laboratory at the University of California at Berkeley will discuss DNA translocation and looping mechanism of chromatin remodeling revealed by single-molecule studies on January 30 at 4 p.m.
The event will be held in the UTD Founders Hall auditorium (FO 3.616). The talk will be preceded by a reception beginning at 3:30 p.m. in the same location. The presentation is open and free to the public.
Dr. Zhang has been doing both experimental and theoretical work in DNA mechanics, chromatin dynamics, and mechanism of chromatin-associated molecular motors. He has received his Ph.D. in molecular biophysics and biochemistry from Yale University.
ATP-dependent chromatin remodeling complexes (remodelers) facilitate the binding of proteins to nucleosomal DNA, transfer histone octamers in cis or trans, assemble chromatin, or exchange histones. Despite their diverse functions, all remodelers share a highly conserved catalytic ATPase domain and are capable of altering nucleosomal DNA configuration, suggesting a conserved mechanism.
Several models for chromatin remodeling have been proposed, but its molecular mechanism remains controversial. Here, we monitor the real-time activity of the SWI/SNF-family remodelers ySWI/SNF and RSC, on single, stretched nucleosomal array templates. We show that these remodelers are ATP- and nucleosome-dependent DNA translocases.
They are capable of moving at rates of ~14 bp/sec and of generating forces up to ~12 pN with processivities of ~100 bp, producing intranucleosomal DNA loops of a broad range of sizes. A DNA loop so formed either dissipates suddenly or reduces its size continuously by what appears to be a reverse translocation. We propose a molecular mechanism for their activity.
Background information on optical tweezers, chromatin remodeling, and remodeler-catalyzed Brownian motion will be provided.
This event is part of the Department of Molecular and Cell Biology and Department of Physics Colloquium series, School of Natural Sciences and Mathematics.
For more information contact Don Gray or Yuri Gartstein.
Updated: 2006-01-25
