InterPro domain: IPR036371

Thiamin pyrophosphokinase (TPK, 2.7.6.2 ) catalyzes the transfer of a pyrophosphate group from ATP to vitamin B1 (thiamin) to form the coenzyme thiamin pyrophosphate (TPP). Thus, TPK is important for the formation of a coenzyme required for central metabolic functions. The structure of thiamin pyrophosphokinase suggest that the enzyme may operate by a mechanism of pyrophosphoryl transfer similar to those described for pyrophosphokinases functioning in nucleotide biosynthesis [ 1 ].

TPK is a homodimer, and each subunit consists of two domains. One domain resembles a Rossman fold, while the other domain forms a beta-sheet flattened sandwich structure containing a jelly-roll topology. The active site is located in a cleft at the dimer interface and is formed from residues from domains of both subunits. The thiamin binding site is primarily defined by the sandwich domain of one subunit and by a loop from the alpha-beta domain of the other subunit [ 2 ]. This superfamily describes the jelly-roll sandwich domain.

1. The crystal structure of yeast thiamin pyrophosphokinase. Structure 9, 539-46