1MFD

THE SOLUTION STRUCTURE OF A TRISACCHARIDE-ANTIBODY COMPLEX: COMPARISON OF NMR MEASUREMENTS WITH A CRYSTAL STRUCTURE


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.10 Å
  • R-Value Work: 0.183 
  • R-Value Observed: 0.183 

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This is version 2.0 of the entry. See complete history


Literature

Solution structure of a trisaccharide-antibody complex: comparison of NMR measurements with a crystal structure.

Bundle, D.R.Baumann, H.Brisson, J.R.Gagne, S.M.Zdanov, A.Cygler, M.

(1994) Biochemistry 33: 5183-5192

  • DOI: https://doi.org/10.1021/bi00183a023
  • Primary Citation of Related Structures:  
    1MFD

  • PubMed Abstract: 

    NMR and crystallography have been used to study antigen conformational changes that occur in a trisaccharide-Fab complex in solution and in the solid state. NOE buildup rates from transferred NOE experiments show that the antigenic determinant of a Salmonella lipopolysaccharide, represented by the trisaccharide methyl glycoside alpha-D-Galp(1-->2 [alpha-D-Abep(1-->3)]- alpha-D-Manp1-->OMe (1), undergoes a protein-induced conformational shift about the Gal-->Man glycosidic linkage when it is bound by a monoclonal antibody in aqueous solution. The same trisaccharide was crystallized with Fab, and a solved structure at 2.1-A resolution revealed that the conformation of the trisaccharide ligand was similar to that seen in a dodesaccharide-Fab complex [Cygler et al. (1991) Science 253, 442-445), where the Gal-Man linkage also experienced a similar conformational shift. Distance constraints derived from the TRNOE buildup curves are consistent with two bound trisaccharide conformations, one of which correlates with the ligand conformation of the crystalline Fab-trisaccharide complex. In this bound conformation, short interatomic distances between Abe O-2 and Gal O-2 permit an oligosaccharide intramolecular hydrogen bond. Despite its relatively low energy, a preponderance of this conformer could not be detected in aqueous or DMSO solutions of free trisaccharide by either 1H or 13C NMR experiments. In DMSO, a different intramolecular hydrogen bond between Abe O-2 and Man O-4 was observed due to a solvent-induced shift in the conformational equilibria (relative to aqueous solution). Molecular modeling of the trisaccharide in the binding site and as the free ligand suggested that the protein imposes an induced fit on the antigen, primarily resulting in a shift of the Gal-Man phi torsional angle. This reduces the interproton separation between Abe H-3 and Gal H-1 with a marked increase in the intensity of the previously weak NOEs between the protons of the noncovalently linked galactose and abequose residues. The impact of the conformational shift on gross trisaccharide topology is sufficiently small that binding modes inferred from functional group replacements are not impaired.


  • Organizational Affiliation

    Institute for Biological Sciences, National Research Council of Canada, Ottawa, Ontario.


Macromolecules
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Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
IGG1-LAMBDA SE155-4 FAB (LIGHT CHAIN)A [auth L]215Mus musculusMutation(s): 0 
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  • Reference Sequence
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Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
IGG1-LAMBDA SE155-4 FAB (HEAVY CHAIN)B [auth H]219Mus musculusMutation(s): 0 
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  • Reference Sequence
Oligosaccharides

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Entity ID: 3
MoleculeChains Length2D Diagram Glycosylation3D Interactions
alpha-D-galactopyranose-(1-2)-[alpha-D-Abequopyranose-(1-3)]methyl alpha-D-mannopyranosideC [auth A]3N/A
Glycosylation Resources
GlyTouCan:  G57118TE
GlyCosmos:  G57118TE
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.10 Å
  • R-Value Work: 0.183 
  • R-Value Observed: 0.183 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 47.3α = 90
b = 129.3β = 90
c = 79.9γ = 90
Software Package:
Software NamePurpose
X-PLORmodel building
X-PLORrefinement
X-PLORphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1994-01-31
    Type: Initial release
  • Version 1.1: 2008-03-24
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 2.0: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Advisory, Atomic model, Data collection, Database references, Derived calculations, Other, Structure summary