Structural Characterization of the EphA4-Ephrin-B2 Complex Reveals New Features Enabling Eph-Ephrin Binding Promiscuity

EphA and EphB receptors preferentially bind ephrin-A and ephrin-B ligands, respectively, but EphA4 is exceptional for its ability to bind all ephrins. Here, we report the crystal structure of the EphA4 ligand-binding domain in complex with ephrin-B2, which represents the first structure of an EphA-e...

Full description

Saved in:
Bibliographic Details
Published in:The Journal of biological chemistry 2010-01, Vol.285 (1), p.644-654
Main Authors: Qin, Haina, Noberini, Roberta, Huan, Xuelu, Shi, Jiahai, Pasquale, Elena B., Song, Jianxing
Format: Article
Language:English
Subjects:
Calorimetry
Cell Line
Crystallography, X-Ray
Ephrin-B2 - chemistry
Ephrin-B2 - metabolism
Humans
Kinetics
Ligands
Magnetic Resonance Spectroscopy
Models, Molecular
Mutant Proteins - chemistry
Mutant Proteins - metabolism
Protein Binding
Protein Multimerization
Protein Structure and Folding
Protein Structure, Secondary
Receptor, EphA4 - chemistry
Receptor, EphA4 - metabolism
Solutions
Substrate Specificity
Thermodynamics
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:EphA and EphB receptors preferentially bind ephrin-A and ephrin-B ligands, respectively, but EphA4 is exceptional for its ability to bind all ephrins. Here, we report the crystal structure of the EphA4 ligand-binding domain in complex with ephrin-B2, which represents the first structure of an EphA-ephrin-B interclass complex. A loose fit of the ephrin-B2 G-H loop in the EphA4 ligand-binding channel is consistent with a relatively weak binding affinity. Additional surface contacts also exist between EphA4 residues Gln12 and Glu14 and ephrin-B2. Mutation of Gln12 and Glu14 does not cause significant structural changes in EphA4 or changes in its affinity for ephrin-A ligands. However, the EphA4 mutant has ∼10-fold reduced affinity for ephrin-B ligands, indicating that the surface contacts are critical for interclass but not intraclass ephrin binding. Thus, EphA4 uses different strategies to bind ephrin-A or ephrin-B ligands and achieve binding promiscuity. NMR characterization also suggests that the contacts of Gln12 and Glu14 with ephrin-B2 induce dynamic changes throughout the whole EphA4 ligand-binding domain. Our findings shed light on the distinctive features that enable the remarkable ligand binding promiscuity of EphA4 and suggest that diverse strategies are needed to effectively disrupt different Eph-ephrin complexes.
ISSN:0021-9258
1083-351X
DOI:10.1074/jbc.M109.064824