Sandbox Reserved 1121: Difference between revisions

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=== Phosphocholine-binding site ===

[[Image:Phosphocholine.PNG | thumb | PC and Ca2+-binding site <ref name="PyMol"/>]]

PC ~~stands for phosphocholine. It~~ is a phospholipid in cell membranes and a plasma lipoprotein <ref name="Thompson"/>. The PC-binding site is a hydrophobic pocket constituted by the residues Leu64, Phe66, Thr76 and the two Ca2+ <ref name="agrawal"/>.

Phosphocholine(PC) is a phospholipid in cell membranes and a plasma lipoprotein <ref name="Thompson"/>. The PC-binding site is a hydrophobic pocket constituted by the residues Leu64, Phe66, Thr76 and the two Ca2+ <ref name="agrawal"/><ref name="Volanakis"/>. This residues are very important because if one of them is mutated into an other, the avidity is significantly reduced <ref name="Volanakis"/>.

Two of the oxygens of the phosphate group directly co-ordinate with the two Ca2+ bound on the CRP <ref name="Volanakis"/>, leaving the third oxygen pointing away from the binding sites <ref name="Thompson"/>.The choline group rests within the hydrophobic pocket.

The three choline methyl groups makes hydrophobic interactions with the exposed face of Phe66, while, the positively charged quartenary choline nitrogen interacts with the side of Glu81 which is located on the other side of the pocket <ref name="Volanakis"/>.

The choline function of PC interacts with the two key residues Phe66 and Glu81, therefore PC lies inside the PC-binding site <ref name="kumar"/> <ref name="agrawal"/>.

The PC-binding site is next to the Ca2+-binding sites on the same face of the CRP protein. The phosphate groupe of PC interacts by coordination with the two Ca2+ <ref name="agrawal"/>.

The affinity of CRP for PC increases ~~with~~ the concentration of PC. A surface containing a high density of PC, such as C-polycaccharide, is therefore propitious to the CRP-binding <ref name="duclos"/>.

The affinity of CRP for PC increases when the concentration of PC does so. A surface containing a high density of PC, such as C-polycaccharide, is therefore propitious to the CRP-binding <ref name="duclos"/>.

CRP can also bind chromatin, histones, small nuclear ribonucleoproteins nuclear envelop proteins and nucleosomes Ca2+-dependently <ref name="agrawal"/>.

== Function ==

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 === Phosphocholine-binding site ===
 [[Image:Phosphocholine.PNG | thumb | PC and Ca<sup>2+</sup>-binding site <ref name="PyMol"/>]]
-PC stands for phosphocholine. It is a phospholipid in cell membranes and a plasma lipoprotein <ref name="Thompson"/>. The PC-binding site is a hydrophobic pocket constituted by the residues Leu64, Phe66, Thr76 and the two Ca<sup>2+</sup> <ref name="agrawal"/>.
+Phosphocholine(PC) is a phospholipid in cell membranes and a plasma lipoprotein <ref name="Thompson"/>. The PC-binding site is a hydrophobic pocket constituted by the residues Leu64, Phe66, Thr76 and the two Ca<sup>2+</sup> <ref name="agrawal"/><ref name="Volanakis"/>. This residues are very important because if one of them is mutated into an other, the avidity is significantly reduced <ref name="Volanakis"/>.
+Two of the oxygens of the phosphate group directly co-ordinate with the two Ca<sup>2+</sup> bound on the CRP <ref name="Volanakis"/>, leaving the third oxygen pointing away from the binding sites  <ref name="Thompson"/>.The choline group rests within the hydrophobic pocket.
+The three choline methyl groups makes hydrophobic interactions with the exposed face of Phe66, while, the positively charged quartenary choline nitrogen interacts with the side of Glu81 which is located on the other side of the pocket <ref name="Volanakis"/>.
 The choline function of PC interacts with the two key residues Phe66 and Glu81, therefore PC lies inside the PC-binding site <ref name="kumar"/> <ref name="agrawal"/>.
-The PC-binding site is next to the Ca<sup>2+</sup>-binding sites on the same face of the CRP protein. The phosphate groupe of PC interacts by coordination with the two Ca<sup>2+</sup> <ref name="agrawal"/>.
-The affinity of CRP for PC increases with the concentration of PC. A surface containing  a high density of PC, such as C-polycaccharide, is therefore propitious to the CRP-binding <ref name="duclos"/>.
+The affinity of CRP for PC increases when the concentration of PC does so. A surface containing a high density of PC, such as C-polycaccharide, is therefore propitious to the CRP-binding <ref name="duclos"/>.
 CRP can also bind chromatin, histones, small nuclear ribonucleoproteins nuclear envelop proteins and nucleosomes Ca<sup>2+</sup>-dependently <ref name="agrawal"/>.
 == Function ==