Pterin-binding domain (IPR000489)

Short name: Pterin-binding_dom

Overlapping homologous superfamilies

Domain relationships


The ~250-residue pterin-binding domain has been shown to adopt a (beta/alpha)8 barrel fold, which has the overall shape of a distorted cylinder. It has eight alpha-helices stacked around the outside of an inner cylinder of parallel beta-strands. The pterin ring binds at the bottom of the (beta/alpha;)8 barrel in a polar cup-like region that is relatively solvent exposed and fairly negatively charged. The pterin ring is partially buried within the (beta/alpha)8 barrel. The pterin binding residues are highly conserved and include aspartate and asparagine residues located at the C terminus of the beta-strands of the barrel, which are predicted to form hydrogen bonds with the nitrogen and oxygen atoms of the pterin ring [PMID: 10997901, PMID: 9187658, PMID: 14752199].

Some proteins known to contain a pterin-binding domain are listed below:

  • Prokaryotic and eukaryotic B12-dependent methionine synthase (MetH) (EC:, a large, modular protein that catalyzes the transfer of a methyl group from methyltetrahydrofolate (CH3-H4folate) to Hcy to form methionine, using cobalamin as an intermediate methyl carrier.
  • Prokaryotic and eukaryotic dihydropteroate synthase (DHPS) (EC: It catalyzes the condensation of para-aminobenzoic acid (pABA) with 7,8- dihydropterin-pyrophosphate (DHPPP), eliminating pyrophosphate to form 7,8- dihydropteroate which is subsequently converted to tetrahydrofolate.
  • Moorella thermoacetica 5-methyltetrahydrofolate corrinoid/iron sulphur protein methyltransferase (MeTr). It transfers the N5-methyl group from CH3-H4folate to a cob(I)amide centre in another protein, the corrinoid iron sulphur protein.

GO terms

Biological Process

GO:0042558 pteridine-containing compound metabolic process

Molecular Function

No terms assigned in this category.

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
PROSITE patterns
PROSITE patterns
PROSITE profiles