Structure-specific recognition protein (IPR000969)

Short name: SSrcognition

Overlapping homologous superfamilies


Family relationships



Human structure-specific recognition protein, SSRP1, [PMID: 1372440] binds specifically to DNA modified with the anti-cancer drug cisplatin. An 81kDa protein is predicted, containing several highly-charged domains and a stretch of 75 residues that share 47% identity with a portion of the high mobility group (HMG) protein HMG1. This HMG box probably constitutes the structure recognition element for cisplatin-modified DNA, the probable recognition motif being the local duplex unwinding and bending that occurs on formation of intra-strand cross-links [PMID: 1372440]. SSRP1 is the human homologue of a recently identified mouse protein that binds to recombination signal sequences [PMID: 1678855]. These sequences have been postulated to form stem-loop structures, further implicating local bends and unwinding in DNA as a recognition target for HMG-box proteins. A Drosophila melanogaster cDNA encoding an HMG-box-containing protein has also been isolated [PMID: 7688122, PMID: 8479916]. This protein shares 50% sequence identity with human SSRP1. In vitro binding studies using Drosophila SSRP showed that the protein binds to single-stranded DNA and RNA, with highest affinity for nucleotides G and U. Comparison of the predicted amino acid sequences among SSRP family members reveals 48% identity, with structural conservation in the C terminus of the HMG box, as well as domains of highly charged residues. The most highly conserved regions lie in the poorly understood N terminus, suggesting that this portion of the protein is critical for its function [PMID: 8479916].

This entry contains Pob3 Q04636, which is a subunit of the heterodimeric yeast FACT complex (Spt16p (IPR013953)-Pob3p) [PMID: 15987999]. The FACT complex facilitates RNA Polymerase II transcription elongation through nucleosomes by destabilising and then reassembling nucleosome structure [PMID: 12524332, PMID: 12934006].

GO terms

Biological Process

No terms assigned in this category.

Molecular Function

GO:0003677 DNA binding

Cellular Component

GO:0005634 nucleus

Contributing signatures

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