Probing the structure of RecA-DNA filaments. Advantages of a fluorescent guanine analog

Tetrahedron. 2007 Apr 23;63(17):3553-3566. doi: 10.1016/j.tet.2006.10.092.


The RecA protein of Escherichia coli plays a crucial roles in DNA recombination and repair, as well as various aspects of bacterial pathogenicity. The formation of a RecA-ATP-ssDNA complex initiates all RecA activities and yet a complete structural and mechanistic description of this filament has remained elusive. An analysis of RecA-DNA interactions was performed using fluorescently labeled oligonucleotides. A direct comparison was made between fluorescein and several fluorescent nucleosides. The fluorescent guanine analog 6-methylisoxanthopterin (6MI) demonstrated significant advantages over the other fluorophores and represents an important new tool for characterizing RecA-DNA interactions.