1Q2H image
Entry Detail
PDB ID:
1Q2H
Title:
Phenylalanine Zipper Mediates APS Dimerization
Biological Source:
Source Organism:
PDB Version:
Deposition Date:
2003-07-24
Release Date:
2004-08-03
Method Details:
Experimental Method:
Resolution:
1.70 Å
R-Value Free:
0.27
R-Value Work:
0.25
Space Group:
P 21 21 2
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:adaptor protein with pleckstrin homology and src homology 2 domains
Chain IDs:A, B, C
Chain Length:69
Number of Molecules:3
Biological Source:Homo sapiens
Primary Citation
A phenylalanine zipper mediates APS dimerization.
Nat.Struct.Mol.Biol. 11 968 974 (2004)
PMID: 15378031 DOI: 10.1038/nsmb829

Abstact

The APS, SH2-B and LNK proteins are adapters that activate and modulate receptor tyrosine kinase and JAK/STAT signaling. We now show that a conserved N-terminal domain mediates APS homodimerization. We determined the crystal structure of the dimerization domain at a resolution of 1.7 A using bromide ion MAD phasing. Each molecule contributes two helices to a compact four-helix bundle having a bisecting-U topology. Its most conspicuous feature is a stack of interdigitated phenylalanine side chains at the domain core. These residues create a new motif we refer to as a 'phenylalanine zipper,' which is critical to dimerization. A newly developed bridging yeast tri-hybrid assay showed that APS dimerizes JAK2, insulin receptor and IGF1 receptor kinases using its SH2 and dimerization domains. Dimerization via the phenylalanine zipper domain provides a mechanism for activating and modulating tyrosine kinase activity even in the absence of extracellular ligands.

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