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The galactan‐binding immunoglobulin Fab J539: An x‐ray diffraction study at 2.6‐Å resolution
Author(s) -
Suh Se Won,
Bhat T. N.,
Navia Manuel A.,
Cohen Gerson H.,
Rao D. N.,
Rudikoff Stuart,
Davies David R.
Publication year - 1986
Publication title -
proteins: structure, function, and bioinformatics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.699
H-Index - 191
eISSN - 1097-0134
pISSN - 0887-3585
DOI - 10.1002/prot.340010112
Subject(s) - galactan , resolution (logic) , antibody , immunoglobulin fab fragments , chemistry , crystallography , computational biology , biology , computer science , immunoglobulin light chain , biochemistry , immunology , artificial intelligence , enzyme , complementarity determining region
The crystal structure of the Fab of the galactan‐binding immunoglobulin J539 (a mouse IgA,κ) has been determined at a resolution of approximately 2.6 Å by X‐ray diffraction. The starting model was that obtained from the real space search described previously (Navia, M.A., Segal, D.M., Padlan, E.A., Davies, D.R., Rao, D.N., Rudikoff, S. and Potter, M. “Crystal structure of galactan‐binding mouse immunoglobulin J539 Fab at 4.5 Å resolution.” Proc. Nat. Acad. Sci. USA, 76:4071–4074, 1979). This Fab structure has now been refined by restrained least‐squares procedures to an R‐value of 19% for the 11,690 unique reflections between 8.0 Å and 2.6 Å. The rms deviation from ideal bond lengths is 0.025 Å. The overall structure differs from McPC603 Fab, another mouse IgA,κ antibody, in that the elbow bend, relating the variable and constant parts of the molecule, is 145° vs. 133° for McPC603. The region of the molecule expected to be the antigen binding site contains a large cavity with two clefts leading away from it. This has been fitted with a model of an oligo‐galactan.