Has very low affinity for the DHPS substrate 6-hydroxymethyl-7,8-dihydropterin-pyrophosphate, but can bind the inhibitor dapsone. Seems to lack dihydropteroate synthase activity, and does probably not function in folate metabolism. Homodimer. Belongs to the DHPS family. A histidine residue in the pterin-binding domain interferes with substrate binding, and seems to be responsible for abolishing dihydropteroate synthase activity.