Credit: Zhou et al./ Nature 2017
A close-up view of the three-component interaction between synaptotagmin (yellow), complexin (blue), and the SNARE complex (purple and red) in a brain cell. The curly helix of complexin nestles near a helix in a synaptotagmin protein, and is arranged so that twists of the helices align like the threads of a screw. These helices rest atop helices of the SNARE complex.