BTB

Broad-Complex, Tramtrack and Bric a brac
BTB
SMART accession number:SM00225
Description: Domain in Broad-Complex, Tramtrack and Bric a brac. Also known as POZ (poxvirus and zinc finger) domain. Known to be a protein-protein interaction motif found at the N-termini of several C2H2-type transcription factors as well as Shaw-type potassium channels. Known structure reveals a tightly intertwined dimer formed via interactions between N-terminal strand and helix structures. However in a subset of BTB/POZ domains, these two secondary structures appear to be missing. Be aware SMART predicts BTB/POZ domains without the beta1- and alpha1-secondary structures.
Interpro abstract (IPR000210):

The BTB domain (Broad-Complex, Tramtrack and Bric a brac) is also known as the POZ domain (POxvirus and Zinc finger). It is a homodimerization domain occurring at the N terminus of proteins containing multiple copies of either zinc fingers of the C2H2 type or Kelch repeats [ (PUBMED:7938017) (PUBMED:7958847) ]. Many BTB proteins are transcriptional regulators that are thought to act through the control of chromatin structure.

The structure of the BTB domain of the promyelocytic leukemia zinc finger (PLZF) protein has been determined by X-ray crystallography and reveals a tightly intertwined dimer with an extensive hydrophobic interface [ (PUBMED:9770450) ]. A surface-exposed groove lined with conserved amino acids is formed at the dimer interface, suggesting a peptide-binding site.

GO function:protein binding (GO:0005515)
Family alignment:
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There are 113741 BTB domains in 107385 proteins in SMART's nrdb database.

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