1BM3: Immunoglobulin Opg2 Fab-peptide Complex

Antibodies are important tools to explore receptor-ligand interactions. The anti-integrin antibody OPG2 binds in an RGD-related manner to the alphaIIb beta3 integrin as a molecular mimic of fibrinogen. The Fab fragment from OPG2 was cocrystallized with a peptide from the beta3 subunit of the integrin representing a site that binds RGD. The crystal structure of the complex was determined at 2.2-A resolution and compared with the unbound Fab. On binding the integrin peptide there were conformational changes in CDR3 of the heavy chain. Also, a significant shift across the intermolecular interface between the CH1-CL domains was observed so that the angle of rotation relating the two domains was reduced by 15 degrees. This unusual conformational adjustment represents the first example of ligand-induced conformational changes in the carboxyl domains of a Fab fragment.
PDB ID: 1BM3Download
MMDB ID: 10161
PDB Deposition Date: 1999/4/15
Updated in MMDB: 2017/10
Experimental Method:
x-ray diffraction
Resolution: 2  Å
Source Organism:
Similar Structures:
Biological Unit for 1BM3: dimeric; determined by author and by software (PISA)
Molecular Components in 1BM3
Label Count Molecule
Proteins (2 molecules)
Immunoglobulin Opg2 Fab, Constant Domain
Molecule annotation
Immunoglobulin Opg2 Fab, Variable Domain
Molecule annotation
* Click molecule labels to explore molecular sequence information.

Citing MMDB