HMPP kinase is a key enzyme in the biosynthetic pathway for the formation of thiamine. The bacterial form of the enzyme described here is a member of the ribokinase/sugar kinase family, meaning that it displays significant sequence and structural homology with a large number of kinases with different substrates such as Adenosine kinase. It is unusual however because it is able to catalyse two consecutive steps in the synthesis of thiamine; phosphorylation of 4-amino-5-hydroxymethyl-5-methyl pyrimidine (HM) to give HMP followed by phosphorylation of HMP to give HMPP. This makes studying the enzyme interesting for understanding the specificity of the active site.
Defined by 6 residues: LYS:A-198 [auth A-176]THR:A-230 [auth A-208]GLY:A-232 [auth A-210]THR:A-233 [auth A-211]GLY:A-234 [auth A-212]CYS:A-235 [auth A-213]