Spatial Organization of Biological Fuctions | BPS Thematic Meeting

Spatial Organization of Biological Functions Meeting

Tuesday Speaker Abstracts

MOLECULAR MECHANISM OF NAPs: HOW Lsr2 AND H-NS SCULPT THE BATERIAL GENOME Manipal Ganji Indian Institute of Science, Bangalore, India No Abstract

STOCHASTIC MODELLING OF SEMI-DISCONTINUOUS DNA REPLICATION IN T4 BACTERIOPHAGE Janani Gnanavelan 1 ; Deepak Bhat 1 ; 1 Vellore Institute of Technology, Department of Physics, Vellore, India Every cell must replicate its genome during its life cycle to ensure faithful reproduction. DNA replication inside is carried out by more than one DNA polymerase in coordination with other proteins residing in a protein complex called replisome. Replication is semi-discontinuous: one (leading) strand is synthesized continuously, while the other (lagging) strand is synthesized discontinuously. The short interim fragments formed on the lagging strand are called Okazaki fragments. In this study, we developed a model to simulate the stochastic dynamics of DNA polymerases on the lagging strand that reliably reproduces the experimentally observed Okazaki fragment size distributions of the T4 replisome. Our analysis reveals that collisions with pre synthesized Okazaki fragments trigger the dissociation of DNA polymerase from the lagging strand. We support this central conclusion through multiple pieces of evidence, including simulations that resolve contradictory experimental observations. Furthermore, our analysis rules out the possibility of involvement of more than polymerase on the lagging strand. These results help clarify the mechanics of polymerase dynamics and offer a quantitative basis for future experimental investigations.

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