First Draft

“Direct imaging of RecA nucleation and growth on single molecules of SSB-coated ssDNA” Jason C. Bell, Jody L. Plank, Christopher C. Dombrowski, and Stephen C. Kowalczykowski

Background

To ensure their survival, cells have evolved mechanisms by which they both monitor genome integrity and repair damage. The most dangerous type of DNA damage is double stranded breaks (DSB) which can be caused by endogenously generated oxygen radicals, replication forks encountering single stranded DNA breaks or other DNA lesions, or exogenous agents such as ionizing radiation or chemotherapeutic drugs [3].

Introduction

There are two main options for repairing a DSB: homologous recombination (HR) and non-homologous end joining (NHEJ) [3]. The focus of this paper is proteins, specifically RecA and SSB, involved in homologous recombination in E. coli.

RecA

RecA is a 38kDA ATPase, a class of enzymes that catalyze the hydrolysis of ATP, found in Escherichia coli that is essential for DNA repair and maintenance (1).

References

1. Bell, Jason C., Plank, Jody L., Dombrowski, Christopher C., and Kowalczykowski. Direct imaging of RecA nucleation and growth on single molecules of SSB-coated ssDNA. Nature 491, 274 - 278 (2012).
2. Chen, Z., Yang, H., Pavletich, N.P. Machanism of homolgous recombination from the RecA-ssDNA/dsDNA strucures. Nature 435. 489-494 (2008)