TY  - JOUR
AU  - Stief, Tobias
AU  - Gremer, Lothar
AU  - Pribicevic, Sonja
AU  - Espinueva, Delane F.
AU  - Vormann, Katharina
AU  - Biehl, Ralf
AU  - Jahn, Reinhard
AU  - Pérez-Lara, Ángel
AU  - Lakomek, Nils
TI  - Intrinsic Disorder of the Neuronal SNARE Protein SNAP25a in its Pre-fusion Conformation
JO  - Journal of molecular biology
VL  - 435
IS  - 10
SN  - 0022-2836
CY  - Amsterdam [u.a.]
PB  - Elsevier
M1  - FZJ-2023-03208
SP  - 168069 -
PY  - 2023
AB  - The neuronal SNARE protein SNAP25a (isoform 2) forms part of the SNARE complex eliciting synaptic vesicle fusion during neuronal exocytosis. While the post-fusion cis-SNARE complex has been studied extensively, little is known about the pre-fusion conformation of SNAP25a. Here we analyze monomeric SNAP25a by NMR spectroscopy, further supported by small-angle X-ray scattering (SAXS) experiments. SAXS data indicate that monomeric SNAP25 is more compact than a Gaussian chain but still a random coil. NMR shows that for monomeric SNAP25a, before SNAP25a interacts with its SNARE partners to drive membrane fusion, only the N-terminal part (region A5 to V36) of the first SNARE motif, SN1 (L11 - L81), is helical, comprising two α-helices (ranging from A5 to Q20 and S25 toV36). From E37 onwards, SNAP25a is mostly disordered and displays high internal flexibility, including the C-terminal part of SN1, almost the entire second SNARE motif (SN2, N144-A199), and the connecting loop region. Apart from the N-terminal helices, only the C-termini of both SN1 (E73 - K79) and SN2 (region T190 - A199), as well as two short regions in the connecting loop (D99 - K102 and E123 - M127) show a weak α-helical propensity (α-helical population < 25%). We speculate that the N-terminal helices (A5 to Q20 and S25 to V36) which constitute the N-terminus of SN1 act as a nucleation site for initiating SNARE zippering.
LB  - PUB:(DE-HGF)16
C6  - 37003471
UR  - <Go to ISI:>//WOS:001030007700001
DO  - DOI:10.1016/j.jmb.2023.168069
UR  - https://juser.fz-juelich.de/record/1014224
ER  -