| Type: | Family | Name: | Structure-specific recognition protein |
| Description: | Human structure-specific recognition protein, SSRP1, [] 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 []. SSRP1 is the human homologue of a recently identified mouse protein that binds to recombination signal sequences []. 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 melanogastercDNA encoding an HMG-box-containing protein has also been isolated [, ]. 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 [].This entry contains Pob3 , which is a subunit of the heterodimeric yeast FACT complex (Spt16p ()-Pob3p) []. The FACT complex facilitates RNA Polymerase II transcription elongation through nucleosomes by destabilising and then reassembling nucleosome structure [, ]. | Short Name: | SSrcognition |
