2nup
From Proteopedia
Crystal Structure of the human Sec23a/24a heterodimer, complexed with the SNARE protein Sec22b
Contents |
Overview
The mechanism of cargo concentration into ER-derived vesicles involves interactions between the COPII vesicular coat complex and cargo transport signals--peptide sequences of 10-15 residues. The SNARE protein Sec22 contains a signal that binds the COPII subcomplex Sec23/24 and specifies its endoplasmic reticulum (ER) exit as an unassembled SNARE. The 200 kDa crystal structure of Sec22 bound to Sec23/24 reveals that the transport signal is a folded epitope rather than a conventional short peptide sequence. The NIE segment of the SNARE motif folds against the N-terminal longin domain, and this closed form of Sec22 binds at the Sec23/24 interface. Thus, COPII recognizes unassembled Sec22 via a folded epitope, whereas Sec22 assembly into SNARE complexes would mask the NIE segment. The concept of a conformational epitope as a transport signal suggests packaging mechanisms in which a coat is sensitive to the folded state of a cargo protein or the assembled state of a multiprotein complex.
Disease
Known disease associated with this structure: Craniolenticulosutural dysplasia OMIM:[610511]
About this Structure
2NUP is a Protein complex structure of sequences from Homo sapiens. Full crystallographic information is available from OCA.
Reference
The transport signal on Sec22 for packaging into COPII-coated vesicles is a conformational epitope., Mancias JD, Goldberg J, Mol Cell. 2007 May 11;26(3):403-14. PMID:17499046 Page seeded by OCA on Thu Jun 5 10:08:11 2008
