Sandbox Reserved 1121: Difference between revisions

Line 9:

=== 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 determined 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"/>.

The crystal structure of CRP was determined by using SAP as the search model <ref name="Thompson"/>. The structure of CRP has been determined 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 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"/>.

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 <ref name="Volanakis"/>. 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"/>.

In each subunit, we can distinguish 2 faces: A and B. Two calcium ions are bound 4 Å apart by protein sidechains coming from loops collected at the concave face (B) and this is the site of ligand binding <ref name="Thompson"/>. The A face is recognizable by the presence of a single α-helix, meaning that this face of the pentamer shows five helices. There is also a marked furrow of 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"/>. 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"/>. This face can interact with C1q and Fc receptors <ref name="duclos">PMID: 15531769 </ref><ref name="Volanakis"/>. Asp112 seems to be an important residue for recognition of Cq1 by CRP <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.

Sandbox Reserved 1121: Difference between revisions

Navigation menu

Page actions

Page actions

Personal tools

Navigation

Search

Tools

@@ Line 9: / Line 9: @@
 === 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 determined 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"/>.
+The crystal structure of CRP was determined by using SAP as the search model  <ref name="Thompson"/>. The structure of CRP has been determined 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 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"/>.
 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 <ref name="Volanakis"/>. 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"/>.
 In each subunit, we can distinguish 2 faces: A and B. Two calcium ions are bound 4 Å apart by protein sidechains coming from loops collected at the concave face (B) and this is the site of ligand binding <ref name="Thompson"/>. The A face is recognizable by the presence of a single α-helix, meaning that this face of the pentamer shows five helices. There is also a marked furrow of 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"/>. 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"/>. This face can interact with C1q and Fc receptors <ref name="duclos">PMID: 15531769 </ref><ref name="Volanakis"/>. Asp112 seems to be an important residue for recognition of Cq1 by CRP <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.