Sandbox Reserved 1121: Difference between revisions

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=== CRP structure ===

The crystal structure of CRP was determined by using SAP as ~~the search~~ model <ref name="Thompson"/>. The structure of CRP has been obtained by X-ray crystallography at 3 Å resolution. Like SAP, the protein consists of five protomers, uncovalently bonded and nonglycosylated that are arranged symmetrically around a central pore <ref name="Volanakis">PMID: 11532280</ref>. Each subunit is a 25 kDa protein consisting of 224 residues <ref name="uniprot">[http://www.uniprot.org/uniprot/P02741 UniProtKB - P02741 (CRP_HUMAN)]</ref>. The diameter of the CRP pentamer is 102 Å, the inner pore diameter is 30 Å and the diameter of a subunit is 36 Å <ref name="agrawal">PMID: 19799114 </ref><ref name="Volanakis"/>. Ser53, His95, Cys97, Asp112, Gly113, Gly136, Gly154, Val165, Leu166, Ile171, and Gly196 are the highliest conserved residues in the primary sequence of CRP <ref name="kumar"/>.

The crystal structure of CRP was determined by using SAP as a research model<ref name="Thompson"/>. The structure of CRP has been obtained by X-ray crystallography at 3 Å resolution. Like SAP, the protein consists of five protomers, uncovalently bonded and nonglycosylated that are arranged symmetrically around a central pore<ref name="Volanakis">PMID: 11532280</ref>. Each subunit is a 25 kDa protein consisting of 224 residues<ref name="uniprot">[http://www.uniprot.org/uniprot/P02741 UniProtKB - P02741 (CRP_HUMAN)]</ref>. The diameter of the CRP pentamer is 102 Å, the inner pore diameter is 30 Å and the diameter of a subunit is 36 Å<ref name="agrawal">PMID: 19799114 </ref><ref name="Volanakis"/>. Ser53, His95, Cys97, Asp112, Gly113, Gly136, Gly154, Val165, Leu166, Ile171, and Gly196 are the highliest conserved residues in the primary sequence of CRP<ref name="kumar"/>.

Each subunit consist of two antiparallel <scene name='71/719862/Sheet/1'>β-sheets</scene> <ref name="uniprot"/> with a flattened jellyroll topology <ref name="Volanakis"/> and a long <scene name='71/719862/Helix/1'>α-helix</scene> (residues 168-176) lies folded against the β-sheets. The predominant structure is β-sheet <ref>PMID: 1382589</ref> but short helical regions can be noticed for the residues 43 and 185 <ref name="kumar"/>. The carboxyl terminal end of the helix along with loop 177-182 form one of the two sides of a cleft that extends from the centre of the protomer to its edge at the central pore of the pentamer <ref name="Volanakis"/>. The other side of the cleft is formed by parts of the amino and carboxyl termini of the protomer <ref name="Volanakis"/>. This furrow is 24 Å long, 7.5 Å deep and 12.4 Å wide. The side walls are constructed from Ser5, Arg6, Gln203, Pro206, Trp187, Arg188, Asn160, Gly177, Leu176, Tyr175, His95 and Asp112 <ref name="Thompson"/>. This cleft is involved in C1q binding and perhaps also with the neutrophils Fc Receptor <ref name="duclos">PMID: 15531769 </ref><ref name="Volanakis"/>.The outer part of the furrow is positively charged but the inner part terminates halfway through the pentamer pore at residue Asp112, providing a ring of negative charges lining the pore <ref name="Thompson"/>. Asp112 seems to be an important residue for recognition of Cq1 by CRP <ref name="Thompson"/> because it is considered, with Tyr175, to be C1q contact residues. Glu88 seems to influence the conformational change of C1q necessary for complement activation, while Asn158 and His38 may contribute to the correct geometry of the binding site <ref name="Volanakis"/>.

Each subunit consist of two antiparallel <scene name='71/719862/Sheet/1'>β-sheets</scene><ref name="uniprot"/> with a flattened jellyroll topology<ref name="Volanakis"/> and a long <scene name='71/719862/Helix/1'>α-helix</scene> (residues 168-176) lies folded against the β-sheets. The predominant structure is β-sheet <ref>PMID: 1382589</ref> but short helical regions can be noticed for the residues 43 and 185<ref name="kumar"/>. The carboxyl terminal end of the helix along with loop 177-182 form one of the two sides of a cleft that extends from the centre of the protomer to its edge at the central pore of the pentamer <ref name="Volanakis"/>. The other side of the cleft is formed by parts of the amino and carboxyl termini of the protomer <ref name="Volanakis"/>. This furrow is 24 Å long, 7.5 Å deep and 12.4 Å wide. The side walls are constructed from Ser5, Arg6, Gln203, Pro206, Trp187, Arg188, Asn160, Gly177, Leu176, Tyr175, His95 and Asp112 <ref name="Thompson"/>. This cleft is involved in C1q binding and perhaps also with the neutrophils Fc Receptor <ref name="duclos">PMID: 15531769 </ref><ref name="Volanakis"/>.The outer part of the furrow is positively charged but the inner part terminates halfway through the pentamer pore at residue Asp112, providing a ring of negative charges lining the pore <ref name="Thompson"/>. Asp112 seems to be an important residue for recognition of Cq1 by CRP <ref name="Thompson"/> because it is considered, with Tyr175, to be C1q contact residues. Glu88 seems to influence the conformational change of C1q necessary for complement activation, while Asn158 and His38 may contribute to the correct geometry of the binding site <ref name="Volanakis"/>.

On the other face of the protomer (face A), two calcium ions are bound 4 Å apart by protein sidechains coming from loops collected at the concave face (face B) and this is the site of ligand binding <ref name="Thompson"/>. Each subunit in CRP is rotated by 22° towards the fivefold axis such that the helices of face A are 5 Å closer to the axis and the calcium sites on face B move away by an equivalent amount <ref name="Volanakis"/><ref name="Thompson"/>.

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 === CRP structure ===
-The crystal structure of CRP was determined by using SAP as the search model  <ref name="Thompson"/>. The structure of CRP has been obtained by X-ray crystallography at 3 Å resolution. Like SAP, the protein consists of five protomers, uncovalently bonded and nonglycosylated that are arranged symmetrically around a central pore <ref name="Volanakis">PMID: 11532280</ref>. Each subunit is a 25 kDa protein consisting of 224 residues  <ref name="uniprot">[http://www.uniprot.org/uniprot/P02741 UniProtKB - P02741 (CRP_HUMAN)]</ref>. The diameter of the CRP pentamer is 102 Å, the inner pore diameter is 30 Å and the diameter of a subunit is 36 Å <ref name="agrawal">PMID: 19799114 </ref><ref name="Volanakis"/>. Ser53, His95, Cys97, Asp112, Gly113, Gly136, Gly154, Val165, Leu166, Ile171, and Gly196 are the highliest conserved residues in the primary sequence of CRP <ref name="kumar"/>.
+The crystal structure of CRP was determined by using SAP as a research model<ref name="Thompson"/>. The structure of CRP has been obtained by X-ray crystallography at 3 Å resolution. Like SAP, the protein consists of five protomers, uncovalently bonded and nonglycosylated that are arranged symmetrically around a central pore<ref name="Volanakis">PMID: 11532280</ref>. Each subunit is a 25 kDa protein consisting of 224 residues<ref name="uniprot">[http://www.uniprot.org/uniprot/P02741 UniProtKB - P02741 (CRP_HUMAN)]</ref>. The diameter of the CRP pentamer is 102 Å, the inner pore diameter is 30 Å and the diameter of a subunit is 36 Å<ref name="agrawal">PMID: 19799114 </ref><ref name="Volanakis"/>. Ser53, His95, Cys97, Asp112, Gly113, Gly136, Gly154, Val165, Leu166, Ile171, and Gly196 are the highliest conserved residues in the primary sequence of CRP<ref name="kumar"/>.
-Each subunit consist of two antiparallel <scene name='71/719862/Sheet/1'>β-sheets</scene> <ref name="uniprot"/> with a flattened jellyroll topology <ref name="Volanakis"/> and a long <scene name='71/719862/Helix/1'>α-helix</scene> (residues 168-176) lies folded against the β-sheets. The predominant structure is β-sheet <ref>PMID: 1382589</ref> but short helical regions can be noticed for the residues 43 and 185 <ref name="kumar"/>.  The carboxyl terminal end of the helix along with loop 177-182 form one of the two sides of a cleft that extends from the centre of the protomer to its edge at the central pore of the pentamer <ref name="Volanakis"/>. The other side of the cleft is formed by parts of the amino and carboxyl termini of the protomer <ref name="Volanakis"/>. This furrow is 24 Å long, 7.5 Å deep and 12.4 Å wide. The side walls are constructed from Ser5, Arg6, Gln203, Pro206, Trp187, Arg188, Asn160, Gly177, Leu176, Tyr175, His95 and Asp112 <ref name="Thompson"/>. This cleft is involved in C1q binding and perhaps also with the neutrophils Fc Receptor <ref name="duclos">PMID: 15531769 </ref><ref name="Volanakis"/>.The outer part of the furrow is positively charged but the inner part terminates halfway through the pentamer pore at residue Asp112, providing a ring of negative charges lining the pore <ref name="Thompson"/>. Asp112 seems to be an important residue for recognition of Cq1 by CRP <ref name="Thompson"/> because it is considered, with Tyr175, to be C1q contact residues. Glu88 seems to influence the conformational change of C1q necessary for complement activation, while Asn158 and His38 may contribute to the correct geometry of the binding site <ref name="Volanakis"/>.
+Each subunit consist of two antiparallel <scene name='71/719862/Sheet/1'>β-sheets</scene><ref name="uniprot"/> with a flattened jellyroll topology<ref name="Volanakis"/> and a long <scene name='71/719862/Helix/1'>α-helix</scene> (residues 168-176) lies folded against the β-sheets. The predominant structure is β-sheet <ref>PMID: 1382589</ref> but short helical regions can be noticed for the residues 43 and 185<ref name="kumar"/>.  The carboxyl terminal end of the helix along with loop 177-182 form one of the two sides of a cleft that extends from the centre of the protomer to its edge at the central pore of the pentamer <ref name="Volanakis"/>. The other side of the cleft is formed by parts of the amino and carboxyl termini of the protomer <ref name="Volanakis"/>. This furrow is 24 Å long, 7.5 Å deep and 12.4 Å wide. The side walls are constructed from Ser5, Arg6, Gln203, Pro206, Trp187, Arg188, Asn160, Gly177, Leu176, Tyr175, His95 and Asp112 <ref name="Thompson"/>. This cleft is involved in C1q binding and perhaps also with the neutrophils Fc Receptor <ref name="duclos">PMID: 15531769 </ref><ref name="Volanakis"/>.The outer part of the furrow is positively charged but the inner part terminates halfway through the pentamer pore at residue Asp112, providing a ring of negative charges lining the pore <ref name="Thompson"/>. Asp112 seems to be an important residue for recognition of Cq1 by CRP <ref name="Thompson"/> because it is considered, with Tyr175, to be C1q contact residues. Glu88 seems to influence the conformational change of C1q necessary for complement activation, while Asn158 and His38 may contribute to the correct geometry of the binding site <ref name="Volanakis"/>.
 On the other face of the protomer (face A), two calcium ions are bound 4 Å apart by protein sidechains coming from loops collected at the concave face (face B) and this is the site of ligand binding <ref name="Thompson"/>. Each subunit in CRP is rotated by 22° towards the fivefold axis such that the helices of face A are 5 Å closer to the axis and the calcium sites on face B move away by an equivalent amount <ref name="Volanakis"/><ref name="Thompson"/>.