RGD Reference Report - The Habc domain and the SNARE core complex are connected by a highly flexible linker. - Rat Genome Database
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The Habc domain and the SNARE core complex are connected by a highly flexible linker.

Authors: Margittai, Martin  Fasshauer, Dirk  Jahn, Reinhard  Langen, Ralf 
Citation: Margittai M, etal., Biochemistry. 2003 Apr 15;42(14):4009-14.
RGD ID: 12793015
Pubmed: (View Article at PubMed) PMID:12680753
DOI: Full-text: DOI:10.1021/bi027437z

Syntaxin 1a is a member of the SNARE superfamily of small, mostly membrane-bound proteins that mediate membrane fusion in all eukaryotic cells. Upon membrane fusion, syntaxin 1 forms a stable complex with its partner SNAREs. Syntaxin contains a C-terminal transmembrane domain, an adjacent SNARE motif that interacts with its partner SNAREs, and an N-terminal Habc domain. The Habc domain reversibly folds back upon the SNARE motif, resulting in a "closed" conformation that is stabilized by binding to the protein munc18. The SNARE motif and the Habc domain are separated by a linker region of about 40 amino acids. When syntaxin is complexed with munc18, the linker is structured and consists of a mix of turns and small alpha-helices. When syntaxin is complexed with its partner SNAREs, the Habc domain is dissociated, but the structure of the linker region is not known. Here we used site-directed spin labeling and EPR spectroscopy to determine the structure of the linker region of syntaxin in the SNARE complex. We found that the entire linker region of syntaxin is unstructured except for three residues at the N-terminal and six residues at the C-terminal boundary whereas the structures of the flanking regions in the Habc domain and the SNARE motif correspond to the high-resolution structures of the isolated fragments. We conclude that the linker region exhibits a high degree of conformational flexibility.


Gene Ontology Annotations    

Biological Process

Cellular Component

Molecular Function

Objects Annotated

Genes (Rattus norvegicus)
Snap25  (synaptosome associated protein 25)
Stx1a  (syntaxin 1A)
Vamp2  (vesicle-associated membrane protein 2)

Additional Information