Butyrophylin-like, SPRY domain (IPR003879)

Short name: Butyrophylin_SPRY

Domain relationships


Several proteins that contain RING fingers also contain a well-conserved 40-residue cysteine-rich domain termed a B-box zinc finger. Often, one or two copies of the B-box are associated with a coiled coil domain in addition to the ring finger, forming a tripartite motif. The tripartite motif is found in transcription factors, ribonucleoproteins and proto-oncoproteins, but no function has yet been ascribed to the domain [PMID: 9923704].

The solution structure of the B-box motif has been determined by NMR. The protein is a monomer, with 2 beta-strands, 2 helical turns and 3 extended loop regions packed in a novel topology [PMID: 8846787]. Of 7 potential zinc ligands, only 4 are used, binding a single zinc atom in a C2-H2 tetrahedral arrangement. The B-box structure differs in tertiary fold from all other known zinc-binding motifs.

A group of proteins that contain the B-box motif also host a well conserved domain of unknown function. Proteins that include this domain are, e.g.: butyrophilin, the RET finger protein, the 52kDa Ro protein and the Xenopus nuclear factor protein. The C-terminal portion of this region has been termed the SPRY domain (after SPla and the RYanodine Receptor) [PMID: 9923704].

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.