HMG-box

The HMG-box (High Mobility Group box) is a protein domain which is involved in DNA binding.

Structure
The structure of the HMG-box domain contains three alpha helices separated by loops (see figure to the right).

Function
HMG-box containing proteins only bind non-B-type DNA conformations (kinked or unwound) with high affinity. HMG-box domains are found in high mobility group proteins, which are involved in the regulation of DNA-dependent processes such as transcription, replication, and DNA repair, all of which require changing the conformation of chromatin.