Abstract 1330 Structural basis for optimized double-strand-break repair activity of a domesticated group II intron-like RT

This study investigates the structural adaptations of G2L4 RT, a bacterial group II intron-like reverse transcriptase (RT) that evolved to function in double-strand break repair (DSBR) via microhomology-mediated end joining (MMEJ). Crystal structures of the G2L4 RT apoenzyme (2.6 Å) and bound to a snap-back DNA synthesis substrate (2.8 Å) were determined. The apoenzyme structure revealed a novel RT3a knot that blocks the active site, stabilizing an inactive conformation until encountering an appropriate substrate.