2NUT

Crystal Structure of the human Sec23a/24a heterodimer, complexed with the SNARE protein Sec22b

Summary for 2NUT

• Entry DOI: 10.2210/pdb2nut/pdb
• Related: 1IFQ 1M2V 2NUP
• Descriptor: Protein transport protein Sec23A, Protein transport protein Sec24A, Vesicle-trafficking protein SEC22b, ... (5 entities in total)
• Functional Keywords: human copii sec23-24 complexed with sec22, protein transport
• Biological source: Homo sapiens (human); More
• Cellular location: Cytoplasmic vesicle, COPII-coated vesicle membrane ; Peripheral membrane protein ; Cytoplasmic side : Q15436 O95486; Endoplasmic reticulum membrane ; Single-pass type IV membrane protein : O75396
• Total number of polymer chains: 3
• Total formula weight: 194060.82

Authors

Mancias, J.D.,Goldberg, J. (deposition date: 2006-11-09, release date: 2007-05-22, Last modification date: 2023-08-30)

Primary citation

Mancias, J.D.,Goldberg, J.
The Transport Signal on Sec22 for Packaging into COPII-Coated Vesicles is a Conformational Epitope
Mol.Cell, 26:403-414, 2007

PubMed Abstract: 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.

PubMed: 17499046
DOI: 10.1016/j.molcel.2007.03.017

Experimental method

X-RAY DIFFRACTION (2.3 Å)