serval:BIB_0C4B820E84E4
Syntaxin1a variants lacking an N-peptide or bearing the LE mutation bind to Munc18a in a closed conformation.
10.1073/pnas.1303753110
000322441500041
23858467
Colbert
K.N.
author
Hattendorf
D.A.
author
Weiss
T.M.
author
Burkhardt
P.
author
Fasshauer
D.
author
Weis
W.I.
author
article
2013
Proceedings of the National Academy of Sciences of the United States of America
1091-6490
0027-8424
journal
110
31
12637-12642
In neurons, soluble N-ethylmaleimide-sensitive factor attachment receptor (SNARE) proteins drive the fusion of synaptic vesicles to the plasma membrane through the formation of a four-helix SNARE complex. Members of the Sec1/Munc18 protein family regulate membrane fusion through interactions with the syntaxin family of SNARE proteins. The neuronal protein Munc18a interacts with a closed conformation of the SNARE protein syntaxin1a (Syx1a) and with an assembled SNARE complex containing Syx1a in an open conformation. The N-peptide of Syx1a (amino acids 1-24) has been implicated in the transition of Munc18a-bound Syx1a to Munc18a-bound SNARE complex, but the underlying mechanism is not understood. Here we report the X-ray crystal structures of Munc18a bound to Syx1a with and without its native N-peptide (Syx1aΔN), along with small-angle X-ray scattering (SAXS) data for Munc18a bound to Syx1a, Syx1aΔN, and Syx1a L165A/E166A (LE), a mutation thought to render Syx1a in a constitutively open conformation. We show that all three complexes adopt the same global structure, in which Munc18a binds a closed conformation of Syx1a. We also identify a possible structural connection between the Syx1a N-peptide and SNARE domain that might be important for the transition of closed-to-open Syx1a in SNARE complex assembly. Although the role of the N-peptide in Munc18a-mediated SNARE complex assembly remains unclear, our results demonstrate that the N-peptide and LE mutation have no effect on the global conformation of the Munc18a-Syx1a complex.
Amino Acid Substitution
Humans
Munc18 Proteins/chemistry
Munc18 Proteins/genetics
Peptides
Protein Binding
Protein Structure, Quaternary
Protein Structure, Secondary
SNARE Proteins/chemistry
SNARE Proteins/genetics
Sequence Deletion
Syntaxin 1/chemistry
Syntaxin 1/genetics
eng
60_published
true
peer-reviewed
University of Lausanne
mailto:serval_help@unil.ch
http://www.unil.ch/serval
http://serval.unil.ch/disclaimer
https://serval.unil.ch/notice/serval:BIB_0C4B820E84E4