Browsing by Author "Norwood, S"

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    Low resolution structural studies of Munc18c complexed with a Syntaxin-4/T4- Lysozyme Fusion
    (Australian Institute of Nuclear Science and Engineering, 2016-11-29) Whitten, AE; Rehman, AU; Hu, SH; Tnimov, Z; Christie, MP; King, GJ; Jarrott, RJ; Norwood, S; Alexandrov, K; Collins, BM; Martin, JL
    Soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNARE) act at every intracellular trafficking pathway. Cognate v-SNAREs (e.g. VAMP) and t-SNAREs (Syntaxin (Sx) and SNAP) form a high affinity SNARE ternary complex (Sx-SNAP-VAMP) that brings the membranes together, triggering fusion. Syntaxins consist of a SNARE motif, and a three-helix bundle. In an open confirmation, the SNARE motif is free to form the SNARE ternary complex (stimulating fusion), but in the closed confirmation fusion is inhibited. Sec1p/Munc18 (SM) proteins bind to Sx, regulating SNARE mediated fusion [1], but their exact role is not well understood [2-4]. In the cell, Sx is bound to the membrane, and it is possible that this tethering may influence the manner in which it interacts with other proteins. As a means of investigating structural changes arising due to tethering, here, we investigate how the addition of a C-terminal T4-Lysozyme (soluble) fusion to Sx4 modulates its interaction with Munc18c. Preliminary low-resolution models of the Munc18c-Sx4T4 complex optimized against small-angle scattering data will be presented.