6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase

Function

6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase (HPPK) is a prokaryotic enzyme which is part of the folate synthesis pathway. HPPK catalyzes the attachment of pyrophosphate from ATP to 6-hydroxymethyl-7,8-dihydropterin (HMDP) to form 6-hydroxymethyl-7,8-dihydropteridine pyrophosphate. Mg+2 ion is important for binding ATP and HMDP.^[1]

Relevance

HPPK is a potential target for antimicrobial drugs like trimethoprim and sulfonamides.

Structural highlights

Three loop regions surround the HPPK active site. Upon binding of ATP, the region (purple) changes its conformation and enables the binding of HMDP. . Water molecules are shown as red spheres.