first high mobility group (HMG)-box found in mitochondrial transcription factor A (TFA) and similar proteins
TFA, also called TFAM, mitochondrial transcription factor 1 (TF1), transcription factor 6 (TCF-6), or transcription factor 6-like 2, binds to the mitochondrial light strand promoter and functions in mitochondrial transcription regulation. It is a component of the mitochondrial transcription initiation complex, composed of at least TFB2M, TFAM and POLRMT that is required for basal transcription of mitochondrial DNA. TFA is required for accurate and efficient promoter recognition by the mitochondrial RNA polymerase. It can unwind DNA. It bends the mitochondrial light strand promoter DNA into a U-turn shape via its HMG boxes. TFA is required for maintenance of normal levels of mitochondrial DNA and may play a role in organizing and compacting mitochondrial DNA. TFA contains two HMG-box domains. This model corresponds to the first one.