PROSITE documentation PDOC50972
Pterin-binding domain profile


The ~250-residue pterin-binding domain has been shown to adopt a (β/α)8 barrel fold (see <PDB:1F6Y>), 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 (β/α)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 (β/α)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 [1,2,3].

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 sulfur protein methyltransferase (MeTr). It transfers the N5-methyl group from CH3-H4folate to a cob(I)amide center in another protein, the corrinoid iron sulfur protein.

The profile we developed covers the entire pterin-binding domain.

Last update:

April 2004 / First entry.


Technical section

PROSITE method (with tools and information) covered by this documentation:

PTERIN_BINDING, PS50972; Pterin-binding domain profile  (MATRIX)


1AuthorsDoukov T. Seravalli J. Stezowski J.J. Ragsdale S.W.
TitleCrystal structure of a methyltetrahydrofolate- and corrinoid-dependent methyltransferase.
SourceStructure 8:817-830(2000).
PubMed ID10997901

2AuthorsAchari A. Somers D.O. Champness J.N. Bryant P.K. Rosemond J. Stammers D.K.
TitleCrystal structure of the anti-bacterial sulfonamide drug target dihydropteroate synthase.
SourceNat. Struct. Biol. 4:490-497(1997).
PubMed ID9187658

3AuthorsEvans J.C. Huddler D.P. Hilgers M.T. Romanchuk G. Matthews R.G. Ludwig M.L.
TitleStructures of the N-terminal modules imply large domain motions during catalysis by methionine synthase.
SourceProc. Natl. Acad. Sci. U.S.A. 101:3729-3736(2004).
PubMed ID14752199

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