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2d03
From Proteopedia
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[[Image:2d03.gif|left|200px]] | [[Image:2d03.gif|left|200px]] | ||
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'''Crystal structure of the G91S mutant of the NNA7 Fab''' | '''Crystal structure of the G91S mutant of the NNA7 Fab''' | ||
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[[Category: Wedekind, J E.]] | [[Category: Wedekind, J E.]] | ||
[[Category: Xie, K.]] | [[Category: Xie, K.]] | ||
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| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 23:27:07 2008'' | |
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Revision as of 20:27, 3 May 2008
Crystal structure of the G91S mutant of the NNA7 Fab
Overview
The NNA7 Fab antibody fragment recognizes the human N-type blood-group antigen comprised of the N-terminal glycopeptide of glycophorin A (GPA). A mutant form of this Fab fragment, NNA7-G91S, exhibits markedly reduced antigen binding. To provide insight into how these Fab fragments recognize this glycopeptide antigen, the crystal structures of NNA7 and NNA7-G91S were solved and refined to 1.83 and 1.97 A resolution, respectively. Both molecules are composed of the same heavy (H) chain Fd fragment, but each contains a slightly different light (L) chain owing to the G91S substitution. Specifically, the G91S mutation pushes the backbone of the neighboring H chain away from complementarity-determining region 3 (CDR3) of the L-chain variable region, allowing an additional glycerol cryoprotectant molecule to enter the antigen-combining site near the putative location of O-linked glycosylation. Each Fab fragment also possesses a well defined 2-(N-morpholino)ethanesulfonic acid (MES) molecule trapped in its antigen-combining site, as well as a crystallographic symmetry-related molecule comprising an amino-acid sequence that is virtually identical to the N-terminus of GPA. The MES molecule interacts with the H-chain CDR in a manner reminiscent of antibody-carbohydrate complexes. These results suggest a model for recognition of the glycopeptide antigen that accounts for the deleterious effect of the G91S substitution.
About this Structure
2D03 is a Single protein structure of sequence from Mus musculus. Full crystallographic information is available from OCA.
Reference
Crystallographic analysis of the NNA7 Fab and proposal for the mode of human blood-group recognition., Xie K, Song SC, Spitalnik SL, Wedekind JE, Acta Crystallogr D Biol Crystallogr. 2005 Oct;61(Pt 10):1386-94. Epub 2005, Sep 28. PMID:16204891 Page seeded by OCA on Sat May 3 23:27:07 2008
