In
molecular biology
Molecular biology is the branch of biology that seeks to understand the molecular basis of biological activity in and between cells, including biomolecular synthesis, modification, mechanisms, and interactions. The study of chemical and physi ...
, the HMG-box (high mobility group box) is a
protein domain
In molecular biology, a protein domain is a region of a protein's polypeptide chain that is self-stabilizing and that folds independently from the rest. Each domain forms a compact folded three-dimensional structure. Many proteins consist of ...
which is involved in
DNA binding.
Structure
The structure of the HMG-box domain contains three
alpha helices
The alpha helix (α-helix) is a common motif in the secondary structure of proteins and is a right hand-helix conformation in which every backbone N−H group hydrogen bonds to the backbone C=O group of the amino acid located four residues ear ...
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
High-Mobility Group or HMG is a group of chromosomal proteins that are involved in the regulation of DNA-dependent processes such as
transcription, replication, recombination, and DNA repair.
Families
The HMG proteins are subdivided into 3 supe ...
proteins, which are involved in the regulation of DNA-dependent processes such as
transcription
Transcription refers to the process of converting sounds (voice, music etc.) into letters or musical notes, or producing a copy of something in another medium, including:
Genetics
* Transcription (biology), the copying of DNA into RNA, the fir ...
,
replication, and
DNA repair
DNA repair is a collection of processes by which a cell identifies and corrects damage to the DNA molecules that encode its genome. In human cells, both normal metabolic activities and environmental factors such as radiation can cause DNA da ...
, all of which require changing the
conformation of
chromatin
Chromatin is a complex of DNA and protein found in eukaryotic cells. The primary function is to package long DNA molecules into more compact, denser structures. This prevents the strands from becoming tangled and also plays important roles in r ...
.
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 domains
{{Protein-stub