NMR data in 'Ca2+-dependent release of Synaptotagmin-1 from the SNARE complex on phosphatidylinositol 4,5-bisphosphate-containing membranes' by Voleti, Jaczynska and Rizo, eLife 2020

The Ca2+ sensor synaptotagmin-1 and the SNARE complex cooperate to trigger
neurotransmitter release. Structural studies elucidated three distinct
synaptotagmin-1-SNARE complex binding modes involving ‘polybasic’,
‘primary’ and ‘tripartite’ interfaces of synaptotagmin-1. We investigated
these interactions using NMR and fluorescence spectroscopy.
Synaptotagmin-1 binds to the SNARE complex through the polybasic and
primary interfaces in solution. Ca2+-free synaptotagmin-1 binds to SNARE
complexes anchored on PIP2-containing nanodiscs. R398Q/R399Q and
E295A/Y338W mutations at the primary interface, which strongly impair
neurotransmitter release, disrupt and enhance synaptotagmin-1-SNARE
complex binding, respectively. Ca2+ induces tight binding of
synaptotagmin-1 to PIP2-containing nanodiscs, releasing
synaptotagmin-1-SNARE interactions. Specific effects of mutations in the
polybasic region on Ca2+-dependent synaptotagmin-1-PIP2-membrane
interactions correlate with their effects on release. Our data suggest
that synaptotagmin-1 binds to the SNARE complex through the primary
interface and that Ca2+ releases this interaction, inducing PIP2/membrane
binding and allowing cooperation between synaptotagmin-1 and the SNAREs in
membrane fusion to trigger release.