PDBsum entry 1a14

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Complex (antibody/antigen) PDB id
Protein chains
388 a.a. *
120 a.a. *
104 a.a. *
* Residue conservation analysis

References listed in PDB file
Key reference
Title Three-Dimensional structures of single-Chain fv-Neuraminidase complexes.
Authors R.L.Malby, A.J.Mccoy, A.A.Kortt, P.J.Hudson, P.M.Colman.
Ref. J Mol Biol, 1998, 279, 901-910. [DOI no: 10.1006/jmbi.1998.1794]
PubMed id 9642070
The structure of the complex between a recombinant single-chain Fv construct of antibody NC10 with a five-residue peptide linker between VH and VL (termed scFv(5)), and its antigen, tetrameric neuraminidase from influenza virus (NA), has been determined and refined at 2.5 A resolution. The antibody-antigen binding interface is very similar to that of a similar NC10 scFv-NA complex in which the scFv has a 15-residue peptide linker (scFv(15)), and the NC10 Fab-NA complex. However, scFv(5) and scFv(15) have different stoichiometries in solution. While scFv(15) is predominantly monomeric in solution, scFv(5) forms dimers exclusively, because the five-residue linker is not long enough to permit VH and VL domains from the same polypeptide associating and forming an antigen-binding site. Upon forming a complex with NA, scFv(15) forms a approximately 300 kDa complex corresponding to one NA tetramer binding four scFv(15) monomers, while scFv(5) forms a approximately 590 kDa complex, corresponding to two NA tetramers crosslinked by four bivalent scFv(5) dimers. However, the dimeric scFv(5) in the scFv(5)-NA crystals does not crosslink NA tetramers, and modelling studies indicate that it is not possible to pack four dimeric and simultaneously bivalent scFvs between the NA tetramers with only a five-residue linker between VH and VL. The inability arises from the exacting requirement to orient the two antigen-binding surfaces to bind the tetrameric NA antigen while avoiding steric clashes with NC10 scFv(5) dimers bound to other sites on the NA tetramer. The utility of bivalent or bifunctional scFvs with short linkers may therefore be restricted by the steric constraints imposed by binding multivalent antigens.
Figure 1.
Figure 1. Model of the vert, similar 590 kDa complex observed in solution studies of the NC10 scFv(5)-NA, in which the scFv(5) is dimeric and bivalent [Kortt et al 1997]. Model is shown as a bold C^╬▒trace. The NA tetramers (green and purple) are crosslinked by scFv(5) molecules. The Fv domain bound to the green NA is shown with V[L]yellow and V[H]orange, while the Fv domain bound to the purple NA is shown with V[L]light blue and V[H]dark blue. The scFv(5) is thus shown with one V[L]yellow and the other light blue, and one V[H]orange and the other dark-blue. The complex has point group 422 symmetry. Drawn with MOLSCRIPT [Kraulis 1991] and RASTER3D [Bacon and Anderson 1989 and Merritt and Murphy 1994]. (a) View with the molecular 4-fold axis vertical. (b) View with the molecular 4-fold axis out of the page.
Figure 3.
The above figures are reprinted by permission from Elsevier: J Mol Biol (1998, 279, 901-910) copyright 1998.
Secondary reference #1
Title Recombinant antineuraminidase single chain antibody: expression, Characterization, And crystallization in complex with antigen.
Authors R.L.Malby, J.B.Caldwell, L.C.Gruen, V.R.Harley, N.Ivancic, A.A.Kortt, G.G.Lilley, B.E.Power, R.G.Webster, P.M.Colman.
Ref. Proteins, 1993, 16, 57-63.
PubMed id 8497484
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