Sandbox Reserved 1121: Difference between revisions
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=== Ca<sup>2+</sup> binding-site === | === Ca<sup>2+</sup> binding-site === | ||
CRP is a calcium dependent structure. Effectively, Ca<sup>2+</sup> is required for PC binding, and more precisely for the formation of the PC binding site thanks to structural rearrangements. The protection against denaturation and proteolysis is performed through Ca<sup>2+</sup> binding too. In the absence of Ca<sup>2+</sup>, hCRP is cleaved between Asn145 and Phe146 by nagarse protease, and between Phe146 and Glu147 by pronase. | CRP is a calcium dependent structure. Effectively, Ca<sup>2+</sup> is required for PC binding, and more precisely for the formation of the PC binding site thanks to structural rearrangements. The protection against denaturation and proteolysis is performed through Ca<sup>2+</sup> binding too. In the absence of Ca<sup>2+</sup>, hCRP is cleaved between Asn145 and Phe146 by nagarse protease, and between Phe146 and Glu147 by pronase. | ||
Asp60, Asn61, Glu138, Asp140 and the main-chain carbonyl of Gln139 residues allow the first calcium ion binding, and the second is performed through Glu138, Asp140, Glu147 and Gln150 <ref name="ramadan"> | Asp60, Asn61, Glu138, Asp140 and the main-chain carbonyl of Gln139 residues allow the first calcium ion binding, and the second is performed through Glu138, Asp140, Glu147 and Gln150 <ref name="ramadan">PMID: 12037301</ref>. | ||
The two Ca<sup>2+</sup>-binding sites are overlapping in a loop. In the absence of Ca<sup>2+</sup>, the loop changes conformaion and releases the proteolysis site. Therefore Ca<sup>2+</sup> protects CRP form proteolytic cleavage <ref name="agrawal"/>. | The two Ca<sup>2+</sup>-binding sites are overlapping in a loop. In the absence of Ca<sup>2+</sup>, the loop changes conformaion and releases the proteolysis site. Therefore Ca<sup>2+</sup> protects CRP form proteolytic cleavage <ref name="agrawal"/>. | ||