PROSITE documentation PDOC00630

{PDOC00630}
{PS00792; DHPS_1}
{PS00793; DHPS_2}
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* Dihydropteroate synthase signatures *
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All organisms require reduced folate cofactors  for the synthesis of a variety
of metabolites.  Most  microorganisms  must synthesize folate  de novo because
they lack the  active transport system of higher vertebrate cells which allows
these organisms to use dietary  folates.  Enzymes  that  are  involved  in the
biosynthesis of folates are therefore the target of a variety of antimicrobial
agents such as trimethoprim or sulfonamides.

Dihydropteroate synthase (EC 2.5.1.15) (DHPS)  catalyzes  the  condensation of
6-hydroxymethyl-7,8-dihydropteridine  pyrophosphate to  para-aminobenzoic acid
to form 7,8-dihydropteroate.  This  is  the  second step  in  the  three steps
pathway leading from 6-hydroxymethyl-7,8-dihydropterin  to  7,8-dihydrofolate.
DHPS  is the target  of sulfonamides which  are substrates analog that compete
with para-aminobenzoic acid.

Bacterial DHPS (gene sul or folP) [1] is a protein of  about  275 to 315 amino
acid residues  which  is  either  chromosomally  encoded  or  found on various
antibiotic resistance plasmids. In the  lower eukaryote  Pneumocystis carinii,
DHPS is the C-terminal  domain  of  a  multifunctional folate synthesis enzyme
(gene fas) [2].

We developed two signature patterns for DHPS,  the  first signature is located
in the N-terminal section of these enzymes,  while  the  second  signature  is
located in the central section.

-Consensus pattern: [LIVM]-x-[AG]-[LIVMF](2)-N-x-T-x-[DN]-S-[FLMI]-x-D-x-[SG]
-Sequences known to belong to this class detected by the pattern: ALL.
-Other sequence(s) detected in Swiss-Prot: NONE.

-Consensus pattern: [GE]-[SAV]-x-[LIVM](2)-D-[LIVMF]-G-[GPA]-x(2)-[STA]-x-P
-Sequences known to belong to this class detected by the pattern: ALL.
-Other sequence(s) detected in Swiss-Prot: NONE.

-Last update: December 2004 / Patterns and text revised.

[ 1] Slock J., Stahly D.P., Han C.-Y., Six E.W., Crawford I.P.
     "An apparent Bacillus subtilis folic acid biosynthetic operon
     containing pab, an amphibolic trpG gene, a third gene required for
     synthesis of para-aminobenzoic acid, and the dihydropteroate synthase
     gene."
     J. Bacteriol. 172:7211-7226(1990).
     PubMed=2123867
[ 2] Volpes F., Dyer M., Scaife J.G., Darby G., Stammers D.K., Delves C.J.
     Gene 112:213-218(1992).

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