In
molecular biology
Molecular biology is a branch of biology that seeks to understand the molecule, molecular basis of biological activity in and between Cell (biology), cells, including biomolecule, biomolecular synthesis, modification, mechanisms, and interactio ...
, the HMG-box (high mobility group box) is a
protein domain
In molecular biology, a protein domain is a region of a protein's Peptide, polypeptide chain that is self-stabilizing and that Protein folding, folds independently from the rest. Each domain forms a compact folded Protein tertiary structure, thre ...
which is involved in
DNA binding.
The domain is composed of approximately 75 amino acid residues that collectively mediate the DNA-binding of chromatin-associated high-mobility group proteins. HMG-boxes are present in many transcription factors and chromatin-remodeling complexes, where they can mediate non-sequence or sequence-specific 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 some
high mobility group proteins, which are involved in the regulation of DNA-dependent processes such as
transcription,
replication, and
DNA repair
DNA repair is a collection of processes by which a cell (biology), cell identifies and corrects damage to the DNA molecules that encode its genome. A weakened capacity for DNA repair is a risk factor for the development of cancer. DNA is cons ...
, all of which require changing the
conformation of
chromatin.
The single and the double box HMG proteins alter DNA architecture by inducing bends upon binding.
[D. Murugesapillai ''et al'']
Single-molecule studies of high-mobility group B architectural DNA bending proteins
Biophys Rev (2016) doi:10.1007/s12551-016-0236-4
References
External links
*
DNA-binding substances
Protein superfamilies
Protein domains
{{Protein-stub