ELFT HÍRADÓ

[Insperger Tamás <inspi AT mm.bme.hu>]

MEGHÍVÓ

J. Michael T. Thompson FRS

Department of Applied Mathematics & Theoretical Physics
Cambridge University

Localised buckling, writhing and cutting of the DNA molecule

címmel előadást tart

2008. április 28-án (hétfőn) 15.00 órakor

Az előadás helye: BME, Oktatói klub, K I 65

Minden érdeklődőt szívesen látunk.


Abstract
Single–molecule tests on DNA in a magnetic tweezer experiment allow the 
molecule to be stretched and twisted. Under increasing twist the DNA 
buckles locally and forms a ply (plectoneme) which grows at right–angles 
to the loading axis. Interpreting this in terms of elastic–rod theory 
allows the estimation of important parameters of the molecule.
Certain enzymes, the topoisomerases, play an important role in the human 
cell by cutting the long strands of DNA to release excessive torsional 
stresses. If these are added to the experimental environment, individual 
cuts can be observed, giving vital clues as to how the enzymes operate. 
We shall examine in some detail the energy changes that can be induced 
by two types of topoisomerase.