C1QBP

C1QBP is 282 amino acid in length and has three homologous subunit with its N-terminal 73 amino acid residues cleaved off to produce mature C1QBP. C1QBP appears as a monomer around 33 kDa on SDS-PAGE gel under both reducing and nonreducing condition but migrates as a trimer on size-exclusion chromatography (gel filtration). ==Protein structure==

The crystal structure of C1QBP at 2.25 Å resolution shows a homotrimeric ring displaying symmetry. The individual subunits are held together by noncovalent interactions and forms a doughnut shaped quaternary structure with a central cavity of 20 Å in diameter. Each Subunit of C1QBP has seven β-strand (β1- β7) and three α-helices (α1- α3). C1QBP is negatively charged on its soluble face while the membrane face is predominantly positively charged. ==Interactions==

C1QBP has been shown to interact with Protein kinase D1, BAT2, PRKCD, virus and plasmodium falciparum. Plasma proteins including fibrinogen, FXII and HK have been demonstrated to interact with C1QBP in a zinc dependent manner,. Recently, a tumour homing peptide, LyP-1(CGNKRTRGC) has been shown to selectively bind to C1QBP in tumour expressing cells. ==References==