InterPro domain: IPR044736

The B30.2 domain was first identified as a protein domain encoded by an exon (named B30-2) in the Homo sapiens class I major histocompatibility complex region [ 1 ], whereas the SPRY domain was first identified in a Dictyostelium discoideum kinase splA and mammalian calcium-release channels ryanodine receptors [ 2 ]. B30.2 domain consists of PRY and SPRY subdomains. The SPRY domains (after SPla and the RYanodine Receptor) are shorter at the N terminus than the B30.2 domains. The ~200-residue B30.2/SPRY (for B30.2 and/or SPRY) domain is present in a large number of proteins with diverse individual functions in different biological processes. The B30.2/SPRY domain in these proteins is likely to function through protein-protein interaction [ 3 ].The N-terminal ~60 residues of B30.2/SPRY domains are poorly conserved and, as a consequence, a new domain name PRY was coined for a group of similar sequence segments N-terminal to the SPRY domains [ 4 ]. The B30.2/SPRY domain contains three highly conserved motifs (LDP, WEVE and LDYE) [ 4 ]. The B30.2/SPRY domain adopts a highly distorted, compact beta-sandwich fold with two additional short beta helices at the N terminus. The beta sandwich of the B30.2/SPRY domain consists of two layers of beta sheets: sheet A composed of eight strands and sheet B composed of seven strands. All the beta strands are in antiparallel arrangement [ 5 ]. The 5th beta-strand corresponding to WEVE motif [ 5 ]. Both the N- and C-terminal ends of the B30.2/SPRY domains in general are close to each other [ 6 ].

This is the B30.2/SPRY domain found in Ran binding proteins (RanBPs), such as RanBP M homologue (AtRanBPM) from Arabidopsis [ 6 ], vacuolar import and degradation protein 30 (Vid30) from Saccharomyces cerevisiae and dual specificity protein kinase splA (SPLA) from Dictyostelium discoideum.

1. Evolutionary study of multigenic families mapping close to the human MHC class I region. J. Mol. Evol. 37, 600-12
2. SPRY domains in ryanodine receptors (Ca(2+)-release channels). Trends Biochem. Sci. 22, 193-4
3. Structural and functional insights into the B30.2/SPRY domain. EMBO J. 25, 1353-63
4. B30.2-like domain proteins: a growing family. Biochem. Biophys. Res. Commun. 235, 162-5
5. Protein fold analysis of the B30.2-like domain. Proteins 35, 235-49
6. Interactions of an Arabidopsis RanBPM homologue with LisH-CTLH domain proteins revealed high conservation of CTLH complexes in eukaryotes. BMC Plant Biol 12, 83