Seroatlas · Protein domains

Homeodomain, metazoa

IPR020479

Definition

This entry represents the homeodomain (HD), a protein domain of approximately 60 residues that usually binds DNA. It is encoded by the homeobox sequence [[cite:PMID:26464018], [cite:PMID:17963489]], which was first identified in a number of Drosophila homeotic and segmentation proteins, but is now known to be well-conserved in many other animals, including vertebrates [[cite:PMID:2568852], [cite:PMID:1357790]]. Proteins containing HDs are likely to play an important role in development - most are known to be sequence-specific DNA-binding transcription factors. This domain folds into a globular structure with three α-helices connected by two short loops that harbour a hydrophobic core. The second and third form a helix-turn-helix (HTH) motif, which make intimate contacts with the DNA: while the first helix of this motif helps to stabilise the structure, the second helix binds to DNA via a number of hydrogen bonds and hydrophobic interactions, which occur between specific side chains and the exposed bases and thymine methyl groups within the major groove of the DNA [[cite:PMID:26464018], [cite:PMID:17963489]]. One particularity of the HTH motif in some of these proteins arises from the stereo-chemical requirement for glycine in the turn (position 9 of the motif), which is needed to avoid steric interference of the β-carbon with the main chain: for cro and repressor proteins the glycine appears to be mandatory, while for many of the homeotic and other DNA-binding proteins the requirement is relaxed.

90 human proteins with this domain

Each is a reviewed human protein in the Seroatlas serome and a potential autoantibody target; this domain groups them into one antibody-relevant category. Every entry links to its own record.

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