Protein Domain : Pterin-binding domain IPR000489

Type	Domain
Description	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 α-helices stacked around the outside of an inner cylinder of parallel β-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 β-strands of the barrel, which are predicted to form hydrogen bonds with the nitrogen and oxygen atoms of the pterin ring [ , , ].Some proteins known to contain a pterin-binding domain are listed below: Prokaryotic and eukaryotic B12-dependent methionine synthase (MetH) ( ), 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) ( ). 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.
Short Name	Pterin-binding_dom