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Representation of part of an immunoglobulin:
Fab Fragment

IgG1 proteolytic cleavage by the papain gives two Fab (Fragment antigen binding) fragments and a Fc fragment.
The Fab fragments retain the ability to bind antigen because each contains paired VL and VH domains.

VH corresponds to the V-D-J-REGION (in green (V), orange (DJ)) of the heavy chain.
VL corresponds to the V-J-REGION (in green (V) and yellow (J)) of the light chain.

The corresponding PDB (Protein Data Bank) format file is from Mike's immunoglobulin structure function site (

See also:

  • Representation of part of an immunoglobulin: Fc fragment

    Created: 28/06/2001
    Last updated: Monday, 20-Jan-2020 21:00:18 CET
    Author: Marie-Paule Lefranc
    Editors: Elodie Foulquier, Chantal Ginestoux