Involved in biosynthesis of the thiamine precursor thiazole. Catalyzes the conversion of NAD and glycine to adenosine diphosphate 5-(2-hydroxyethyl)-4-methylthiazole-2-carboxylic acid (ADT), an adenylated thiazole intermediate. The reaction includes an iron-dependent sulfide transfer from a conserved cysteine residue of the protein to a thiazole intermediate. The enzyme can only undergo a single turnover, which suggests it is a suicide enzyme. May have additional roles in adaptation to various stress conditions and in DNA damage tolerance. [ADP-thiazole synthase]-L-cysteine + glycine + NAD(+) = [ADP-thiazole synthase]-dehydroalanine + ADP-5-ethyl-4-methylthiazole-2-carboxylate + 2 H(+) + 3 H2O + nicotinamide Binds 1 Fe cation per subunit. Homooctamer. Expressed at high levels in nodules and shoot tips, and at low levels in roots, flowers, and developing fruits. In nodules, expressed in the infected cortical cells and in the pericycle of the nodule vascular bundle. During the catalytic reaction, a sulfide is transferred from Cys-219 to a reaction intermediate, generating a dehydroalanine residue. This protein may be expected to contain an N-terminal transit peptide but none has been predicted. Belongs to the THI4 family.