4J8G: Crystal Structure Of Alpha-cop/e19 Complex

Cytoplasmic dilysine motifs on transmembrane proteins are captured by coatomer alpha-COP and beta'-COP subunits and packaged into COPI-coated vesicles for Golgi-to-ER retrieval. Numerous ER/Golgi proteins contain K(x)Kxx motifs, but the rules for their recognition are unclear. We present crystal structures of alpha-COP and beta'-COP bound to a series of naturally occurring retrieval motifs-encompassing KKxx, KxKxx and non-canonical RKxx and viral KxHxx sequences. Binding experiments show that alpha-COP and beta'-COP have generally the same specificity for KKxx and KxKxx, but only beta'-COP recognizes the RKxx signal. Dilysine motif recognition involves lysine side-chain interactions with two acidic patches. Surprisingly, however, KKxx and KxKxx motifs bind differently, with their lysine residues transposed at the binding patches. We derive rules for retrieval motif recognition from key structural features: the reversed binding modes, the recognition of the C-terminal carboxylate group which enforces lysine positional context, and the tolerance of the acidic patches for non-lysine residues.
PDB ID: 4J8GDownload
MMDB ID: 108730
PDB Deposition Date: 2013/2/14
Updated in MMDB: 2013/04
Experimental Method:
x-ray diffraction
Resolution: 1.9  Å
Source Organism:
Similar Structures:
Biological Unit for 4J8G: dimeric; determined by author and by software (PISA)
Molecular Components in 4J8G
Label Count Molecule
Proteins (2 molecules)
Coatomer Subunit Alpha(Gene symbol: SPBPJ4664.04)
Molecule annotation
Membrane Glycoprotein E3 Gp19k
Molecule annotation
* Click molecule labels to explore molecular sequence information.

Citing MMDB