Structural analysis of the neuronal SNARE protein syntaxin-1A.
Intracellular trafficking depends on the docking and fusion of transport vesicles with cellular membranes. Central to docking and fusion is the pairing of SNARE proteins (soluble NSF attachment protein receptors) associated with the vesicle and target membranes (v- and t-SNAREs, respectively). Here, the X-ray structure of an N-terminal conserved domain of the neuronal t-SNARE syntaxin-1A was determined to a resolution of 1.9 A using multiwavelength anomalous diffraction. This X-ray structure, which is in general agreement with an NMR structure of a similar fragment, provides new insight into the interaction surface between the N-terminal domain and the remainder of the protein. In vitro characterization of the intact cytoplasmic domain of syntaxin revealed that it forms dimers, and probably tetramers, at low micromolar concentrations, with concomitant structural changes that can be detected by limited proteolysis. These observations suggest that the promiscuity characteristic of pairing between v-SNAREs and t-SNAREs extends to the formation of homo-oligomeric t-SNARE complexes as well. They also suggest a potential role for the neuronal Sec1 protein (nSec1) in preventing the formation of syntaxin multimers.
Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, USA.
J C
JC
Lerman
J
J
Robblee
R
R
Fairman
F M
FM
Hughson
D000954:Antigens, Surface / Q000737:chemistry*; D018360:Crystallography, X-Ray; D019281:Dimerization; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry*; D008958:Models, Molecular; D009419:Nerve Tissue Proteins / Q000737:chemistry*; D009474:Neurons / Q000737:chemistry; D010446:Peptide Fragments / Q000737:chemistry; D011487:Protein Conformation; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry; D050600:SNARE Proteins; D055672:Static Electricity; D050827:Syntaxin 1; D033921:Vesicular Transport Proteins
D000954:Antigens, Surface; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D010446:Peptide Fragments; D011994:Recombinant Proteins; D050600:SNARE Proteins; C494212:STX1A protein, human; D050827:Syntaxin 1; D033921:Vesicular Transport Proteins