Interactions of synaptic vesicles in dense pools studied by SAXS

We will study the structure and interactions of synaptic vesicles (SV) in a model system of a dense SV pool, mimicking the environment of a synapse, including changes following a calcium signal. For this purpose, we will use the combination of the stopped-flow technique for rapid mixing and highly brilliant ESRF undulator radiation. This will extend previous SAXS of dilute SV suspensions (modelled by a form-factor only) to a more physiological assembly under controlled physicochemical conditions (modelled by a form- and structure-factor [6]). The proposal addresses the fundamental physicochemical principles governing the interaction of SVs in the presence of cytosolic proteins in the synapse, in particular synapsin and alpha-synuclein, as well as the changes associated with calcium.