1ntl | pdb_00001ntl
Model of mouse Crry-Ig determined by solution scattering, curve fitting and homology modelling
Structural highlights
Function[CR1L_MOUSE] Acts as a cofactor for complement factor I, a serine protease which protects autologous cells against complement-mediated injury by cleaving C3b and C4b deposited on host tissue. Also acts as a decay-accelerating factor, preventing the formation of C4b2a and C3bBb, the amplification convertases of the complement cascade. Plays a crucial role in early embryonic development by maintaining fetomaternal tolerance. Also acts as a costimulatory factor for T-cells which favors IL-4 secretion.[1] [2] [3] [4] [5] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedComplement receptor-related gene/protein y (Crry) is a cell membrane-bound regulator of complement activation found in mouse and rat. Crry contains only short complement/consensus repeat (SCR) domains. X-ray and neutron scattering was performed on recombinant rat Crry containing the first five SCR domains (rCrry) and mouse Crry with five SCR domains conjugated to the Fc fragment of mouse IgG1 (mCrry-Ig) in order to determine their solution structures at medium resolution. The radius of gyration R(G) of rCrry was determined to be 4.9-5.0 nm, and the R(G) of the cross-section was 1.2-1.5 nm as determined by X-ray and neutron scattering. The R(G) of mCrry-Ig was 6.6-6.7 nm, and the R(G) of the cross-section were 2.3-2.4 nm and 1.3 nm. The maximum dimension of rCrry was 18 nm and that for mCrry-Ig was 26 nm. The neutron data indicated that rCrry and mCrry-Ig have molecular mass values of 45,000 Da and 140,000 Da, respectively, in agreement with their sequences, and sedimentation equilibrium data supported these determinations. Time-derivative velocity experiments gave sedimentation coefficients of 2.4S for rCrry and 5.4S for mCrry-Ig. A medium-resolution model of rCrry was determined using homology models that were constructed for the first five SCR domains of Crry from known crystal and NMR structures, and linked by randomly generated linker peptide conformations. These trial-and-error calculations revealed a small family of extended rCrry structures that best accounted for the scattering and ultracentrifugation data. These were shorter than the most extended rCrry models as the result of minor bends in the inter-SCR orientations. The mCrry-Ig solution data were modelled starting from a fixed structure for rCrry and the crystal structure of mouse IgG1, and was based on conformational searches of the hinge peptide joining the mCrry and Fc fragments. The best-fit models showed that the two mCrry antennae in mCrry-Ig were extended from the Fc fragment. No preferred orientation of the antennae was identified, and this indicated that the accessibility of the antennae for the molecular targets C4b and C3b was not affected by the covalent link to Fc. A structural comparison between Crry and complement receptor type 1 indicated that the domain arrangement of Crry SCR 1-3 is as extended as that of the CR1 SCR 15-17 NMR structure. The extended multidomain solution structures of the complement protein Crry and its chimeric conjugate Crry-Ig by scattering, analytical ultracentrifugation and constrained modelling: implications for function and therapy.,Aslam M, Guthridge JM, Hack BK, Quigg RJ, Holers VM, Perkins SJ J Mol Biol. 2003 Jun 6;329(3):525-50. PMID:12767833[6] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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