3.6.1.28 complex with tripolyphosphate, to 2.3 A resolution and docking solution of substrate thiamine triphosphate. The thiazole ring of the thiamine forms a stacking interaction with Trp53, and the aminopyrimidine ring lies in a pocket defined by His76, Pro191 and Ile195. The triphosphate moiety occupies a similar position as in the enzyme-tripolyphosphate complex, with interactions involving the side chains of Lys11, Arg55, Arg57, Lys65, Arg125 and Lys193 733393 3.6.1.28 hanging drop vapor diffusion method, using 27% (w/v) PEG 3350, 0.1 M Tris (pH 9.0), 0.2 M MgCl2 751047