Sulfotransferase that utilizes 3'-phospho-5'-adenylyl sulfate (PAPS) to catalyze the transfer of a sulfo group to an N-unsubstituted glucosamine linked to a 2-O-sulfo iduronic acid unit on heparan sulfate. Catalyzes the O-sulfation of glucosamine in GlcA2S-GlcNS. Unlike HS3ST1/3-OST-1, does not convert non-anticoagulant heparan sulfate to anticoagulant heparan sulfate (By similarity). May contribute to the pineal circadian physiology (PubMed:12601002). 3'-phosphoadenylyl sulfate + alpha-D-glucosaminyl-[heparan sulfate](n) = 3-sulfo-alpha-D-glucosaminyl-[heparan sulfate](n) + adenosine 3',5'-bisphosphate + H(+) Highly expressed in the brain, in the pineal gland specifically during the daylight hours, and weakly in the olfactory bulb and pineal gland during the night. First detected between postnatal days 5 and 10. Activated by light stimulation at night through the suppression of beta-adrenergic signaling. Belongs to the sulfotransferase 1 family.