Human mitochondrial mTERF wraps around DNA through a left-handed superhelical tandem repeat

The regulation of mitochondrial DNA (mtDNA) processes is slowly being characterized at a structural level. We present here crystal structures of human mitochondrial regulator mTERF, a transcription termination factor also implicated in replication pausing, in complex with double-stranded DNA oligonucleotides containing the tRNA(UUR)(Leu) gene sequence. mTERF comprises nine left-handed helical tandem repeats that form a left-handed superhelix, the Zurdo domain.