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Figure 2
Schematic representation of the proposed binding modes between Munc18 and SNARE proteins. Mode 1: Munc18 binds to a `closed' form of Sx. The N-peptide of Sx binds to a site on Munc18 distinct from the central arched binding cavity. The conformation of the connecting residues between the N-peptide and the Habc domain of Sx in the Munc18/closed Sx-binding mode is unknown (dashed line). Mode 2: Munc18 binds to an `open' form of Sx. Low-resolution solution studies indicate the Munc18 protein binds to an `open' form of Sx, although the details of this binding mode remain to be resolved. Mode 3: Munc18 binds to the N-peptide of Sx. In those proteins where this interaction occurs, the binding mode is highly conserved. Details of this interaction have been defined through crystal structure determination. Mode 4: Munc18 binds to assembled SNARE complex. Although many Munc18 systems have been shown to interact with the pre-assembled SNARE complex (Table 1[link]), the molecular details of this binding mode are unknown, as indicated by the question mark.

IUCrJ
Volume 1| Part 6| October 2014| Pages 505-513
ISSN: 2052-2525
doi:10.1107/S2052252514020727