Sandbox207: Difference between revisions
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Elise Rosati (talk | contribs) No edit summary |
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CRP -- C-reactive protein | CRP -- C-reactive protein | ||
[[Image:Image2.jpg|300px| | [[Image:Image2.jpg|300px|right|thumb| CRP structure]] | ||
==Structure== | |||
- Gene : exon, intron ? | - Gene : exon, intron ? | ||
- Taille de la protéine | - Taille de la protéine | ||
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- Famille | - Famille | ||
===Exon, intron, family=== | |||
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 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. | The Human CRP belongs to the pentraxin family of proteins having five identical, non-covalently associated subunits that form a symmetrical homopentameric ring. The pentraxin family is highly conserved in evolution. | ||
===Size=== | |||
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. | |||
===Detailed strucutre=== | |||
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. | 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. | The recognition face contains the which consists of two coordinated calcium ions next to a hydrophobic pocket in which the phosphocholine rests. | ||
There are 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 | 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. | ||