1VFA

BOUND WATER MOLECULES AND CONFORMATIONAL STABILIZATION HELP MEDIATE AN ANTIGEN-ANTIBODY ASSOCIATION

DOI: 10.2210/pdb1VFA/pdb

Classification: IMMUNOGLOBULIN
Organism(s): Mus musculus
Expression System: Escherichia coli
Mutation(s): No

Deposited: 1993-12-03 Released: 1994-05-31
Deposition Author(s): Bhat, T.N., Poljak, R.J.

Experimental Data Snapshot

Method: X-RAY DIFFRACTION
Resolution: 1.80 Å
R-Value Work: 0.158
R-Value Observed: 0.158

wwPDB Validation 3D Report Full Report

This is version 1.2 of the entry. See complete history.

Literature

Bound water molecules and conformational stabilization help mediate an antigen-antibody association.

Bhat, T.N., Bentley, G.A., Boulot, G., Greene, M.I., Tello, D., Dall'Acqua, W., Souchon, H., Schwarz, F.P., Mariuzza, R.A., Poljak, R.J.

(1994) Proc Natl Acad Sci U S A 91: 1089-1093

PubMed: 8302837 Search on PubMedSearch on PubMed Central
DOI: 10.1073/pnas.91.3.1089
Primary Citation of Related Structures:
1VFB, 1VFA

PubMed Abstract:

We report the three-dimensional structures, at 1.8-A resolution, of the Fv fragment of the anti-hen egg white lysozyme antibody D1.3 in its free and antigen-bound forms. These structures reveal a role for solvent molecules in stabilizing the complex and provide a molecular basis for understanding the thermodynamic forces which drive the association reaction. Four water molecules are buried and others form a hydrogen-bonded network around the interface, bridging antigen and antibody. Comparison of the structures of free and bound Fv fragment of D1.3 reveals that several of the ordered water molecules in the free antibody combining site are retained and that additional water molecules link antigen and antibody upon complex formation. This solvation of the complex should weaken the hydrophobic effect, and the resulting large number of solvent-mediated hydrogen bonds, in conjunction with direct protein-protein interactions, should generate a significant enthalpic component. Furthermore, a stabilization of the relative mobilities of the antibody heavy- and light-chain variable domains and of that of the third complementarity-determining loop of the heavy chain seen in the complex should generate a negative entropic contribution opposing the enthalpic and the hydrophobic (solvent entropy) effects. This structural analysis is consistent with measurements of enthalpy and entropy changes by titration calorimetry, which show that enthalpy drives the antigen-antibody reaction. Thus, the main forces stabilizing the complex arise from antigen-antibody hydrogen bonding, van der Waals interactions, enthalpy of hydration, and conformational stabilization rather than solvent entropy (hydrophobic) effects.

Related Citations:

Small Rearrangements in Structures of Fv and Fab Fragments of an Antibody D1.3 On Antigen Binding
Bhat, T.N., Bentley, G.A., Fischmann, T.O., Boulot, G., Poljak, R.J.
(1990) Nature 347: 483

Organizational Affiliation:

Centre National de la Recherche Scientifique, Unité Associée 359, Institut Pasteur, Paris, France.

Macromolecules

Find similar proteins by:

(by identity cutoff) | Structure

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
IGG1-KAPPA D1.3 FV (LIGHT CHAIN)	A	108	Mus musculus	Mutation(s): 0
Find proteins for P01635 (Mus musculus) Explore P01635 Go to UniProtKB: P01635
Protein Feature View Expand
Reference Sequence

Find similar proteins by:

(by identity cutoff) | Structure

Entity ID: 2
Molecule	Chains	Sequence Length	Organism	Details	Image
IGG1-KAPPA D1.3 FV (HEAVY CHAIN)	B	116	Mus musculus	Mutation(s): 0
Find proteins for P01820 (Mus musculus) Explore P01820 Go to UniProtKB: P01820
Protein Feature View Expand
Reference Sequence