{PDOC50972}
{PS50972; PTERIN_BINDING}
{BEGIN}
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* Pterin-binding domain profile *
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The ~250-residue pterin-binding domain has been shown to adopt a (beta/alpha)8
barrel fold  (see  <PDB:1F6Y>),  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)
   (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.

-Sequences known to belong to this class detected by the profile: ALL.
-Other sequence(s) detected in Swiss-Prot: NONE.
-Last update: April 2004 / First entry.

[ 1] Doukov T., Seravalli J., Stezowski J.J., Ragsdale S.W.
     "Crystal structure of a methyltetrahydrofolate- and
     corrinoid-dependent methyltransferase."
     Structure 8:817-830(2000).
     PubMed=10997901
[ 2] Achari A., Somers D.O., Champness J.N., Bryant P.K., Rosemond J.,
     Stammers D.K.
     "Crystal structure of the anti-bacterial sulfonamide drug target
     dihydropteroate synthase."
     Nat. Struct. Biol. 4:490-497(1997).
     PubMed=9187658
[ 3] Evans J.C., Huddler D.P., Hilgers M.T., Romanchuk G., Matthews R.G.,
     Ludwig M.L.
     "Structures of the N-terminal modules imply large domain motions
     during catalysis by methionine synthase."
     Proc. Natl. Acad. Sci. U.S.A. 101:3729-3736(2004).
     PubMed=14752199; DOI=10.1073/pnas.0308082100

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