View source for Dihydropteroate synthase

{{Short description|Class of enzymes}}
{{infobox enzyme
| Name       = Dihydropteroate synthetase
| EC_number  = 2.5.1.15
| CAS_number = 9055-61-2
| GO_code    = 0004156
| image      = THFsynthesispathway.png
| width      =
| caption    = [[Tetrahydrofolic acid|Tetrahydrofolate]] synthesis pathway 
}}
{{Pfam_box 
| Symbol = Pterin_bind 
| Name = Pterin binding enzyme 
| image = 
| width = 
| caption = 
| Pfam= PF00809
| InterPro= IPR000489
| SMART= 
| Prosite = PDOC00630
| SCOP = 1ajz
| TCDB = 
| OPM family= 
| OPM protein= 
| PDB= 
{{PDB3|1twz}}A:28-230    {{PDB3|1tws}}A:28-230    {{PDB3|1tww}}B:28-230    
{{PDB3|1tx0}}A:28-230    {{PDB3|1tx2}}A:28-230    {{PDB3|1ad1}}B:9-210     
{{PDB3|1ad4}}A:9-210     {{PDB3|1eye}}A:11-220    {{PDB3|1ajz}} :20-228    
{{PDB3|1aj2}} :20-228    {{PDB3|1aj0}} :20-228    {{PDB3|2bmb}}A:509-774   
{{PDB3|1q8a}}B:315-515   {{PDB3|1q7z}}B:315-515   {{PDB3|1q85}}A:315-515   
{{PDB3|1q8j}}A:315-515   {{PDB3|1q7q}}B:315-515   {{PDB3|1q7m}}A:315-515   
{{PDB3|1f6y}}A:1-206     
}}

'''Dihydropteroate synthase''' ('''DHPS''') is an enzyme classified under {{EC number|2.5.1.15}}. It produces [[dihydropteroate]] in [[bacteria]], but it is not expressed in most [[eukaryote]]s including humans. This makes it a useful target for [[sulfonamide (medicine)|sulfonamide]] antibiotics, which compete with the [[4-Aminobenzoic acid|PABA]] precursor.

*  [[dihydropteridine-hydroxymethyl-pyrophosphate|(2-amino-4-hydroxy-7,8-dihydropteridin-6-yl)methyl diphosphate]] + [[4-aminobenzoic acid|4-aminobenzoate]] (PABA) <math>\rightleftharpoons</math> diphosphate + [[dihydropteroate]].

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 that allows these organisms to use dietary folates. Proteins containing this domain include dihydropteroate synthase ({{EC number|2.5.1.15}}) as well as a group of methyltransferase enzymes including methyltetrahydrofolate, corrinoid iron-sulphur protein methyltransferase (MeTr)<ref>{{UniProt Full|Q46389}}</ref> that catalyses a key step in the [[Wood-Ljungdahl pathway]] of carbon dioxide fixation.

Dihydropteroate synthase ({{EC number|2.5.1.15}}) (DHPS) catalyses 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-step pathway leading from 6-hydroxymethyl-7,8-dihydropterin to 7,8-dihydrofolate. DHPS is the target of sulfonamides, which are substrate analogues that compete with para-aminobenzoic acid. Bacterial DHPS (gene sul or folP)<ref name="PUB00002127">{{cite journal |vauthors=Crawford IP, Slock J, Stahly DP, Six EW, Han CY |title=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 |journal=J. Bacteriol. |volume=172 |issue=12 |pages=7211–7226 |year=1990 |doi=10.1128/jb.172.12.7211-7226.1990 |pmid=2123867 |pmc=210846}}</ref> is a protein of about 275 to 315 amino acid residues that is either chromosomally encoded or found on various [[antimicrobial resistance|antibiotic resistance]] plasmids. In the fungus ''[[Pneumocystis jirovecii]]'' (previously ''P. carinii'') DHPS is the C-terminal domain of a multifunctional folate synthesis enzyme (gene fas).<ref name="PUB00001816">{{cite journal |vauthors=Volpe F, Dyer M, Scaife JG, Darby G, Stammers DK, Delves CJ |title=The multifunctional folic acid synthesis fas gene of Pneumocystis carinii appears to encode dihydropteroate synthase and hydroxymethyldihydropterin pyrophosphokinase |journal=Gene |volume=112 |issue=2 |pages=213–218 |year=1992 |pmid=1313386 |doi=10.1016/0378-1119(92)90378-3}}</ref>

==References==
{{reflist}}

==External links==
* {{MeshName|Dihydropteroate+synthetase}}

{{Metabolism of vitamins, coenzymes, and cofactors}}
{{Alkyl and aryl transferases}}
{{Enzymes}}
{{Portal bar|Biology|border=no}}

{{InterPro content|IPR000489}}

[[Category:EC 2.5.1]]


{{2.5-enzyme-stub}}