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Crystallographic analysis of the NNA7 Fab and proposal for the mode of human blood-group recognition.
Acta Crystallogr D Biol Crystallogr. 2005 Oct; 61(Pt 10):1386-94.AC

Abstract

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.

Authors+Show Affiliations

Xie K
Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA.
Song SC
No affiliation info available
Spitalnik SL
No affiliation info available
Wedekind JE
No affiliation info available

MeSH

Alkanesulfonic AcidsAntibodiesAntigensBinding SitesBlood ProteinsCarbohydratesCryoprotective AgentsCrystallography, X-RayElectronsGalactoseGlycerolGlycopeptidesGlycophorinsGlycosylationHumansImmunoglobulin Fab FragmentsImmunoglobulin FragmentsMNSs Blood-Group SystemModels, ChemicalModels, MolecularMolecular ConformationMorpholinesMutationProtein BindingProtein Structure, Tertiary

Pub Type(s)

Journal Article
Research Support, N.I.H., Extramural
Research Support, U.S. Gov't, Non-P.H.S.
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

16204891

Citation

Xie, Kefang, et al. "Crystallographic Analysis of the NNA7 Fab and Proposal for the Mode of Human Blood-group Recognition." Acta Crystallographica. Section D, Biological Crystallography, vol. 61, no. Pt 10, 2005, pp. 1386-94.
Xie K, Song SC, Spitalnik SL, et al. Crystallographic analysis of the NNA7 Fab and proposal for the mode of human blood-group recognition. Acta Crystallogr D Biol Crystallogr. 2005;61(Pt 10):1386-94.
Xie, K., Song, S. C., Spitalnik, S. L., & Wedekind, J. E. (2005). Crystallographic analysis of the NNA7 Fab and proposal for the mode of human blood-group recognition. Acta Crystallographica. Section D, Biological Crystallography, 61(Pt 10), 1386-94.
Xie K, et al. Crystallographic Analysis of the NNA7 Fab and Proposal for the Mode of Human Blood-group Recognition. Acta Crystallogr D Biol Crystallogr. 2005;61(Pt 10):1386-94. PubMed PMID: 16204891.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Crystallographic analysis of the NNA7 Fab and proposal for the mode of human blood-group recognition. AU - Xie,Kefang, AU - Song,Shuh Chyung, AU - Spitalnik,Steven L, AU - Wedekind,Joseph E, Y1 - 2005/09/28/ PY - 2005/06/25/received PY - 2005/07/26/accepted PY - 2005/10/6/pubmed PY - 2005/12/13/medline PY - 2005/10/6/entrez SP - 1386 EP - 94 JF - Acta crystallographica. Section D, Biological crystallography JO - Acta Crystallogr D Biol Crystallogr VL - 61 IS - Pt 10 N2 - 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. SN - 0907-4449 UR - https://www.unboundmedicine.com/medline/citation/16204891/Crystallographic_analysis_of_the_NNA7_Fab_and_proposal_for_the_mode_of_human_blood_group_recognition_ DB - PRIME DP - Unbound Medicine ER -