4j79 | pdb_00004j79
Crystal structure of beta'-COP/PEDVspike complex
Structural highlights
Function[COPB2_YEAST] The coatomer is a cytosolic protein complex that binds to dilysine motifs and reversibly associates with Golgi non-clathrin-coated vesicles, which further mediate biosynthetic protein transport from the ER, via the Golgi up to the trans Golgi network. Coatomer complex is required for budding from Golgi membranes, and is essential for the retrograde Golgi-to-ER transport of dilysine-tagged proteins.[1] [SPIKE_PEDV7] S1 region attaches the virion to the cell membrane by interacting with cell receptors, initiating the infection. Binding to the receptor probably induces conformational changes in the S glycoprotein unmasking the fusion peptide of S2 region and activating membranes fusion. S2 region belongs to the class I viral fusion protein. Under the current model, the protein has at least 3 conformational states: pre-fusion native state, pre-hairpin intermediate state, and post-fusion hairpin state. During viral and target cell membrane fusion, the coiled coil regions (heptad repeats) regions assume a trimer-of-hairpins structure, positioning the fusion peptide in close proximity to the C-terminal region of the ectodomain. The formation of this structure appears to drive apposition and subsequent fusion of viral and target cell membranes (By similarity). Publication Abstract from PubMedCytoplasmic 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. Rules for the recognition of dilysine retrieval motifs by coatomer.,Ma W, Goldberg J EMBO J. 2013 Mar 12. doi: 10.1038/emboj.2013.41. PMID:23481256[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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