Sandbox Reserved 1121: Difference between revisions
From Proteopedia
Jump to navigationJump to search
No edit summary |
No edit summary |
||
| Line 11: | Line 11: | ||
Ser53, His95, Cys97, Asp112, Gly113, Gly136, Gly154, Val165, Leu166, Ile171, and Gly196 are the highly conserved residues in the primary sequence of CRP.<ref name="kumar"/> | Ser53, His95, Cys97, Asp112, Gly113, Gly136, Gly154, Val165, Leu166, Ile171, and Gly196 are the highly conserved residues in the primary sequence of CRP.<ref name="kumar"/> | ||
The C-reactive protein is a homopentamer of non-covalently bound subunits. Each subunit is a 25 Da protein consisting of 224 residues bound together. The secondary structure is formed of four α-helices and three β-sheets (five-stranded, three-stranded and seven-stranded).<ref>http://www.uniprot.org/uniprot/P02741</ref> The predominant structure is β-sheet <ref>http://www.unco.edu/nhs/Chemistry/faculty/dong/pub/pentraxin.pdf</ref> but short helical regions can be notice for residues 43 and 185.<ref name="kumar"/> Residues Glu197 and Lys123 in CRP form an intermolecular ion pair.<ref name="thompson" /> | The C-reactive protein is a homopentamer of non-covalently bound subunits. Each subunit is a 25 Da protein consisting of 224 residues bound together. The secondary structure is formed of four α-helices and three β-sheets (five-stranded, three-stranded and seven-stranded).<ref>http://www.uniprot.org/uniprot/P02741</ref> The predominant structure is β-sheet <ref>http://www.unco.edu/nhs/Chemistry/faculty/dong/pub/pentraxin.pdf</ref> but short helical regions can be notice for residues 43 and 185.<ref name="kumar"/> Residues Glu197 and Lys123 in CRP form an intermolecular ion pair.<ref name="thompson" /> | ||
=== | === 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 | 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">Ramadan, M. A. M., Shrive, A. K., Holden, D., Myles, D. A. A., Volanakis, J. E., Larry J.DeLucas, L. J., Greenhough, T. J. (2002), The three-dimensional structure of calcium-depleted human C-reactive protein from perfectly twinned crystals, Acta Cryst., D58 :992-1001</ref> | 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">Ramadan, M. A. M., Shrive, A. K., Holden, D., Myles, D. A. A., Volanakis, J. E., Larry J.DeLucas, L. J., Greenhough, T. J. (2002), The three-dimensional structure of calcium-depleted human C-reactive protein from perfectly twinned crystals, Acta Cryst., D58 :992-1001</ref> | ||
