2aty: Difference between revisions
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'''Complement receptor chimaeric conjugate CR2-Ig'''<br /> | '''Complement receptor chimaeric conjugate CR2-Ig'''<br /> | ||
==Overview== | ==Overview== | ||
Complement receptor 2 (CR2; CD21) is a membrane-bound regulator of | Complement receptor 2 (CR2; CD21) is a membrane-bound regulator of complement activation, being comprised of 15 or 16 short complement repeat (SCR) domains. A recombinant glycosylated human CR2 SCR 1-2 domain pair was engineered with the Fc fragment of a mouse IgG1 antibody to create a chimaera CR2-Ig containing the major ligand binding domains. Such a chimaera has therapeutic potential as a complement inhibitor or immune modulator. X-ray and neutron scattering and analytical ultracentrifugation identified its domain structure in solution, and provided a comparison with controversial folded-back crystal structures for deglycosylated CR2 SCR 1-2. The radius of gyration R(G) of CR2-Ig was determined to be 5.39(+/-0.14) nm and 5.29(+/-0.01) nm by X-ray and neutron scattering, respectively. The maximum dimension of CR2-Ig was determined to be 17 nm. The molecular mass of CR2-Ig ranged between 101,000 Da and 107,000 Da as determined by neutron scattering and sedimentation equilibrium, in good agreement with the sequence-derived value of 106,600 Da. Sedimentation velocity gave a sedimentation coefficient of 4.49(+/-0.11) S. Stereochemically complete models for CR2-Ig were constructed from crystal structures for the CR2 SCR 1-2 and mouse IgG1 Fc fragments. The two SCR domains and the Fc fragment were joined by randomised conformational peptides. The analysis of 35,000 possible CR2-Ig models showed that only those models in which the two SCR domains were arranged in an open V-shape in random orientations about the Fc fragment accounted for the scattering and sedimentation data. It was not possible to define one single conformational family of Fab-like fragment relative to the Fc fragment. This flexibility is attributed to the relatively long linker sequence and the absence of the antibody light chain from CR2-Ig. The modelling also confirmed that the structure of CR2 SCR 1-2 is more extended in solution than in its crystal structure. | ||
==About this Structure== | ==About this Structure== | ||
2ATY is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens,_mus_musculus Homo sapiens, mus musculus]. Full crystallographic information is available from [http:// | 2ATY is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens,_mus_musculus Homo sapiens, mus musculus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2ATY OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Aslam, M.]] | [[Category: Aslam, M.]] | ||
[[Category: Gilbert, H | [[Category: Gilbert, H E.]] | ||
[[Category: Guthridge, J | [[Category: Guthridge, J M.]] | ||
[[Category: Holers, V | [[Category: Holers, V M.]] | ||
[[Category: Perkins, S | [[Category: Perkins, S J.]] | ||
[[Category: antibody]] | [[Category: antibody]] | ||
[[Category: complement]] | [[Category: complement]] | ||
[[Category: immunoglobulin fold]] | [[Category: immunoglobulin fold]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:30:58 2008'' | ||
Revision as of 17:31, 21 February 2008
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Complement receptor chimaeric conjugate CR2-Ig
OverviewOverview
Complement receptor 2 (CR2; CD21) is a membrane-bound regulator of complement activation, being comprised of 15 or 16 short complement repeat (SCR) domains. A recombinant glycosylated human CR2 SCR 1-2 domain pair was engineered with the Fc fragment of a mouse IgG1 antibody to create a chimaera CR2-Ig containing the major ligand binding domains. Such a chimaera has therapeutic potential as a complement inhibitor or immune modulator. X-ray and neutron scattering and analytical ultracentrifugation identified its domain structure in solution, and provided a comparison with controversial folded-back crystal structures for deglycosylated CR2 SCR 1-2. The radius of gyration R(G) of CR2-Ig was determined to be 5.39(+/-0.14) nm and 5.29(+/-0.01) nm by X-ray and neutron scattering, respectively. The maximum dimension of CR2-Ig was determined to be 17 nm. The molecular mass of CR2-Ig ranged between 101,000 Da and 107,000 Da as determined by neutron scattering and sedimentation equilibrium, in good agreement with the sequence-derived value of 106,600 Da. Sedimentation velocity gave a sedimentation coefficient of 4.49(+/-0.11) S. Stereochemically complete models for CR2-Ig were constructed from crystal structures for the CR2 SCR 1-2 and mouse IgG1 Fc fragments. The two SCR domains and the Fc fragment were joined by randomised conformational peptides. The analysis of 35,000 possible CR2-Ig models showed that only those models in which the two SCR domains were arranged in an open V-shape in random orientations about the Fc fragment accounted for the scattering and sedimentation data. It was not possible to define one single conformational family of Fab-like fragment relative to the Fc fragment. This flexibility is attributed to the relatively long linker sequence and the absence of the antibody light chain from CR2-Ig. The modelling also confirmed that the structure of CR2 SCR 1-2 is more extended in solution than in its crystal structure.
About this StructureAbout this Structure
2ATY is a Single protein structure of sequence from Homo sapiens, mus musculus. Full crystallographic information is available from OCA.
ReferenceReference
Extended flexible linker structures in the complement chimaeric conjugate CR2-Ig by scattering, analytical ultracentrifugation and constrained modelling: implications for function and therapy., Gilbert HE, Aslam M, Guthridge JM, Holers VM, Perkins SJ, J Mol Biol. 2006 Feb 17;356(2):397-412. Epub 2005 Dec 5. PMID:16375923
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