Sandbox207

This page is reserveted for a work from two students in ESBS (A.Butet and E.Rosati) Thanks.

CRP -- C-reactive protein

Structure : - Gene : exon, intron ? - Taille de la protéine - Sécrétion - Structure détaillée - Famille

The CRP gene is located on chromosome 1q23. It is composed of two exons and one intron. This gene is regulated by interleukin-6, the principal inducer of the gene during the acute phase. CRP is secreted by hepatocytes. The Human CRP belongs to the pentraxin family of proteins having five identical, non-covalently associated subunits that form a symmetrical homopentameric ring. Each subunit contains 206 amino acid residues (approximately 23kDa) and is non-glycosylated. The outside diameter of the pentamer is 102 Å, the diameter of the inner core is 30 Å, and the diameter of the protomer is 36 Å. Each promoter consists of two anti-parallel β sheets (the lectin fold) with an α helix on the effector face of the protein. The ligand biding site is located on the concave face of the protein, and is composed of loops with 2 calcium ions bound 4 Å apart by protein side-chains. The recognition face contains the which consists of two coordinated calcium ions next to a hydrophobic pocket in which the phosphocholine rests. It exists interpromoter interactions between the subunits: three salt bridges are included and the 115-123 loop of one protomer and the 40-42 and 197-202 regions of adjacent protomers and involved. Moreover, the subunits are capable to rotate by 15-20° around an axis parallel to the central alpha-helix. This rotation allows the alpha-helices to lie closer together to the pentameric 5-fold axis, and brings the bound Ca2+ further away from it. PC is bound in a shallow surface pocket on each subunit, interacting with the two protein-bound calcium ions by the phosphate group and with Glu81 via the choline moiety. The pentraxin family is highly conserved in evolution.