Crystallization and preliminary X‐ray diffraction of the Munc18c–syntaxin4 1–29 complex

The production of diffraction‐quality crystals of Munc18c, a protein involved in regulating vesicular exocytosis in mammals, is reported. The diffraction resolution of Munc18c crystals was optimized by (i) cocrystallizing with a peptide fragment of the Munc18c functional binding partner syntaxin4, (ii) using nanolitre free‐interface diffusion crystallization‐screening chips and microlitre hanging‐drop vapour diffusion and (iii) applying a post‐crystallization dehydration treatment. Crystals belonging to the cubic space group P 2 1 3, with unit‐cell parameters a = b = c = 170.8 Å, α = β = γ = 90°, were generated that diffract to 3.7 Å resolution on a laboratory X‐ray source.