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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 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) (EC 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 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.

April 2004 / First entry.

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

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

Sequences known to belong to this class detected by the profile: ALL Other sequence(s) detected in Swiss-Prot: NONE

• Domain architecture view of Swiss-Prot proteins matching PS50972 • Retrieve an alignment of Swiss-Prot true positive hits:   Clustal format, color, condensed view  / Clustal format, color  / Clustal format, plain text  / Fasta format • Retrieve the sequence logo from the alignment • Taxonomic tree view of all Swiss-Prot/TrEMBL entries matching PS50972 • Retrieve a list of all Swiss-Prot/TrEMBL entries matching PS50972 • Scan Swiss-Prot/TrEMBL entries against PS50972 • view ligand binding statistics

Matching PDB structures: 1AD1 1AD4 1AJ0 1AJ2 ... [ALL]

1	Authors	Doukov T., Seravalli J., Stezowski J.J., Ragsdale S.W.
	Title	Crystal structure of a methyltetrahydrofolate- and corrinoid-dependent methyltransferase.
	Source	Structure 8:817-830(2000).
	PubMed ID	10997901

2	Authors	Achari A., Somers D.O., Champness J.N., Bryant P.K., Rosemond J., Stammers D.K.
	Title	Crystal structure of the anti-bacterial sulfonamide drug target dihydropteroate synthase.
	Source	Nat. Struct. Biol. 4:490-497(1997).
	PubMed ID	9187658

3	Authors	Evans J.C., Huddler D.P., Hilgers M.T., Romanchuk G., Matthews R.G., Ludwig M.L.
	Title	Structures of the N-terminal modules imply large domain motions during catalysis by methionine synthase.
	Source	Proc. Natl. Acad. Sci. U.S.A. 101:3729-3736(2004).
	PubMed ID	14752199
	DOI	10.1073/pnas.0308082100

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