Sandbox207: Difference between revisions

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===Gene structure, 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.[http://www.rndsystems.com/cb_detail_objectname_SU05_CReactiveProtein.aspx]

: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.

: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. [http://biology.kenyon.edu/BMB/Chime2/2005/Jenny/FRAMES/]

===Detailed strucutre===

Line 34:

: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 are involved. Moreover, the subunits are capable to rotate by 15-20° around an axis parallel to the central alpha-helix.

: Thanks to this rotation, the alpha-helices can lie closer to the axis of the pentamere, therefore bringin the bound Ca2+ further away from it. On each subunit, we can find phosphocholine bound in a shallow surface pocket. With the help of phosphate groups and Glu81 via the choline moiety, the phosphocholine can interact with the two protein-bound ions.

:Moreover, the structure of CRP is different in diseased patients. Indeed, in some pathological conditions, the Human CRP is glycosylated. Analysis of the structure showed the systematic absence of two peptide fragments, one at the N-terminus (loop 1-6) in all patients, the other near the C-terminus (loop 189-191) in patients with osteogenic sarcoma and Cushing's syndrome. In an undiseased individual, glycosylation sites are inacessible due to the presence of the N-terminal. The loss of these two fragments exposed two potential glycosylation sites on a cleft door. The functional areas of the pentraxin structure remains the same since the Ca2+ and phosphocholine sites are on the opposite site of the pentraxin molecule.

:Moreover, the structure of CRP is different in diseased patients. Indeed, in some pathological conditions, the Human CRP is glycosylated. Analysis of the structure showed the systematic absence of two peptide fragments, one at the N-terminus (loop 1-6) in all patients, the other near the C-terminus (loop 189-191) in patients with osteogenic sarcoma and Cushing's syndrome. In an undiseased individual, glycosylation sites are inacessible due to the presence of the N-terminal. The loss of these two fragments exposed two potential glycosylation sites on a cleft door. The functional areas of the pentraxin structure remains the same since the Ca2+ and phosphocholine sites are on the opposite site of the pentraxin molecule. [http://biology.kenyon.edu/BMB/Chime2/2005/Jenny/FRAMES/]

Sandbox207: Difference between revisions

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@@ Line 22: / Line 22: @@
 ===Gene structure, 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.[http://www.rndsystems.com/cb_detail_objectname_SU05_CReactiveProtein.aspx]
 :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.
+: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. [http://biology.kenyon.edu/BMB/Chime2/2005/Jenny/FRAMES/]
 ===Detailed strucutre===
@@ Line 34: / Line 34: @@
 :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 are involved. Moreover, the subunits are capable to rotate by 15-20° around an axis parallel to the central alpha-helix.
 : Thanks to this rotation, the alpha-helices can lie closer to the axis of the pentamere, therefore bringin the bound Ca2+ further away from it. On each subunit, we can find phosphocholine bound in a shallow surface pocket. With the help of phosphate groups and Glu81 via the choline moiety, the phosphocholine can interact with the two protein-bound ions.
-:Moreover, the structure of CRP is different in diseased patients. Indeed, in some pathological conditions, the Human CRP is glycosylated. Analysis of the structure showed the systematic absence of two peptide fragments, one at the N-terminus (loop 1-6) in all patients, the other near the C-terminus (loop 189-191) in patients with osteogenic sarcoma and Cushing's syndrome. In an undiseased individual, glycosylation sites are inacessible due to the presence of the N-terminal. The loss of these two fragments exposed two potential glycosylation sites on a cleft door. The functional areas of the pentraxin structure remains the same since the Ca2+ and phosphocholine sites are on the opposite site of the pentraxin molecule.
+:Moreover, the structure of CRP is different in diseased patients. Indeed, in some pathological conditions, the Human CRP is glycosylated. Analysis of the structure showed the systematic absence of two peptide fragments, one at the N-terminus (loop 1-6) in all patients, the other near the C-terminus (loop 189-191) in patients with osteogenic sarcoma and Cushing's syndrome. In an undiseased individual, glycosylation sites are inacessible due to the presence of the N-terminal. The loss of these two fragments exposed two potential glycosylation sites on a cleft door. The functional areas of the pentraxin structure remains the same since the Ca2+ and phosphocholine sites are on the opposite site of the pentraxin molecule. [http://biology.kenyon.edu/BMB/Chime2/2005/Jenny/FRAMES/]