For 10 points, name this compound, also called vitamin B1.
A derivative of this molecule is sensed by the only riboswitch found in higher eukaryotes, and its binding to that riboswitch creates an unstable splice variant. The complex mutated in Maple Syrup Urine Disease relies on this molecule as a cofactor. In E. Coli its synthesis depends on IscS and the products of an operon with C, E, F, S, G, and H genes, which separately synthesize its hydroxymethylpyrimidine moiety with its thiazole moiety. The ylid form of that thiazole cleaves a carbon-carbon bond on substrates. Transketolase uses this compound as a cofactor, and its also used in an enzyme with E1, E2, and E3 subunits that also uses a (*) lipoic acid tether, the pyruvate dehydrogenase complex. Deficiency of this compound comes in two forms; a wet form in which capillaries lose integrity, and a dry form which causes neuritis. That disease is beriberi. For 10 points, name this compound, also called vitamin B1.
A derivative of this molecule is sensed by the only riboswitch found in higher eukaryotes, and its binding to that riboswitch creates an unstable splice variant.
{Thiamine} [accept {Thiamine pyrophosphate}; or {TPP}; accept {Vitamin B1} before mention]