ISSN:
0948-5023
Keywords:
Keywords: Immunoglobulin superfamily
;
comparative protein structure prediction
;
sequence-structure analysis
;
molecular model
;
solution structure
;
model-structure-comparison
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract The CD28 and CTLA-4 (CD152) receptors on T cells recognize CD80 and CD86 ligands on antigen presenting cells. These interactions provide and control costimulatory signals required for effective T cell activation. CD28 and CTLA-4 belong to the immunoglobulin superfamily (IgSF) and contain a single extracellular ligand binding domain. The three-dimensional (3D) structure of the binding domain of CTLA-4 was modeled previously using a combination of structure-based sequence comparison, IgSF consensus residue analysis, conformational search, and inverse folding calculations. Recently, the 3D structure of CTLA-4 was determined by NMR. Comparison of the modeled and experimentally determined CTLA-4 structure has made it possible to assess the accuracy of our predictions. We found that the overall accuracy of the model was sound and sufficient for a meaningful application of the model in experimental studies. Major errors in the model are limited to the conformation and position of some loops. Our studies on CTLA-4 provide an example for the opportunities and limitations of comparative protein modeling in the presence of low sequence similarity.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s008940050039
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