1dsf
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THE CRYSTAL STRUCTURE OF THE DISULFIDE-STABILIZED FV FRAGMENT OF ANTICANCER ANTIBODY B1: CONFORMATIONAL INFLUENCE OF AN ENGINEERED DISULFIDE BOND
OverviewOverview
A recombinant Fv construct of the B1 monoclonal antibody that recognizes, the LewisY-related carbohydrate epitope on human carcinoma cells has been, prepared. The Fv is composed of the polypeptide chains of the VH and VL, domains expressed independently and isolated as inclusion bodies. The Fv, is prepared by combining and refolding equimolar amounts of guanidine, chloride solubilized inclusion bodies. The Fv is stabilized by an, engineered interchain disulfide bridge between residues VL100 and VH44., This construct has a similar binding affinity as that of the single-chain, construct (Benhar and Pastan, Clin. Cancer Res. 1:1023-1029, 1995). The B1, disulfide-stabilized Fv (BldsFv) crystallizes in space group P6(1)22 with, the unit cell parameters a = b = 80.1 A, and c = 138.1 A. The crystal, structure of the BldsFv has been determined at 2.1-A resolution using the, molecular replacement technique. The final structure has a, crystallographic R-value of 0.187 with a root mean square deviation in, bond distance of 0.014 A and in bond angle of 2.74 degrees. Comparisons of, the BldsFv structure with known structures of Fv regions of other, immunoglobulin fragments shows closely related secondary and tertiary, structures. The antigen combining site of BldsFv is a deep depression 10-A, wide and 17-A long with the walls of the depression composed of residues, many of which are tyrosines, from complementarity determining regions L1, L3, H1, H2, and H3. Model building studies indicate that the LewisY, tetrasaccharide, Fuc-Gal-Nag-Fuc, can be accommodated in the antigen, combining site in a manner consistent with the epitope predicted in, earlier biochemical studies (Pastan, Lovelace, Gallo, Rutherford, Magnani, and Willingham, Cancer Res. 51:3781-3787, 1991). Thus, the engineered, disulfide bridge appears to cause little, if any, distortion in the Fv, structure, making it an effective substitute for the B1 Fab.
About this StructureAbout this Structure
1DSF is a Single protein structure of sequence from Mus musculus. Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure of the disulfide-stabilized Fv fragment of anticancer antibody B1: conformational influence of an engineered disulfide bond., Almog O, Benhar I, Vasmatzis G, Tordova M, Lee B, Pastan I, Gilliland GL, Proteins. 1998 May 1;31(2):128-38. PMID:9593187
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