InterPro domain: IPR000489

General Information

  • Identifier IPR000489
  • Description Pterin-binding domain
  • Number of genes 143
  • Gene duplication stats Loading...
  • Associated GO terms GO:0042558  

Abstract

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 [ 1 , 2 , 3 ].

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

  • Prokaryotic and eukaryotic B12-dependent methionine synthase (MetH) ( 2.1.1.13 ), 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) ( 2.5.1.15 ). 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.


1. Crystal structure of a methyltetrahydrofolate- and corrinoid-dependent methyltransferase. Structure 8, 817-30
2. Crystal structure of the anti-bacterial sulfonamide drug target dihydropteroate synthase. Nat. Struct. Biol. 4, 490-7
3. Structures of the N-terminal modules imply large domain motions during catalysis by methionine synthase. Proc. Natl. Acad. Sci. U.S.A. 101, 3729-36

Species distribution

Gene table

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