F
IPR044843

Trans-isoprenyl diphosphate synthases, bacterial-type

InterPro entry
Short nameTrans_IPPS_bact-type
Overlapping
homologous
superfamilies
 
family relationships

Description

Trans-Isoprenyl Diphosphate Synthases (Trans_IPPS) catalyze a head-to-head (HH) (1'-1) condensation reaction
[9]
. This entry includes squalene and phytoene synthases which catalyze the 1'-1 condensation of two 15-carbon (farnesyl) and 20-carbon (geranylgeranyl) isoprenyl diphosphates, respectively
[2, 6, 4, 5]
. The catalytic site consists of a large central cavity formed by mostly antiparallel α helices with two aspartate-rich regions (DXXXD) located on opposite walls
[3]
. These residues mediate binding of prenyl phosphates
[1]
. A two-step reaction has been proposed for squalene synthase (farnesyl-diphosphate farnesyltransferase) in which, two molecules of FPP react to form a stable cyclopropylcarbinyl diphosphate intermediate, and then the intermediate undergoes heterolysis, isomerization, and reduction with NADPH to form squalene, a precursor of cholesterol. The carotenoid biosynthesis enzyme, phytoene synthase (CrtB), catalyses the condensation reaction of two molecules of geranylgeranyl diphosphate to produce phytoene, a precursor of beta-carotene
[7]
. These enzymes produce the triterpene and tetraterpene precursors for many diverse sterol and carotenoid end products and are widely distributed among eukaryota, bacteria, and archaea
[8]
.

This entry includes squalene and phytoene synthases found in bacteria, archaea, fungi, plant chloroplasts and insects.

References

1.Structure, mechanism and function of prenyltransferases. Liang PH, Ko TP, Wang AH. Eur. J. Biochem. 269, 3339-54, (2002). View articlePMID: 12135472

2.Isoprenyl diphosphate synthases: protein sequence comparisons, a phylogenetic tree, and predictions of secondary structure. Chen A, Kroon PA, Poulter CD. Protein Sci. 3, 600-7, (1994). View articlePMID: 8003978

3.Conversion from archaeal geranylgeranyl diphosphate synthase to farnesyl diphosphate synthase. Two amino acids before the first aspartate-rich motif solely determine eukaryotic farnesyl diphosphate synthase activity. Ohnuma S, Hirooka K, Ohto C, Nishino T. J. Biol. Chem. 272, 5192-8, (1997). View articlePMID: 9030588

4.Chain-length determination mechanism of isoprenyl diphosphate synthases and implications for molecular evolution. Wang K, Ohnuma S. Trends Biochem. Sci. 24, 445-51, (1999). View articlePMID: 10542413

5.Chain elongation in the isoprenoid biosynthetic pathway. Kellogg BA, Poulter CD. Curr Opin Chem Biol 1, 570-8, (1997). View articlePMID: 9667899

6.Structure and regulation of mammalian squalene synthase. Tansey TR, Shechter I. Biochim. Biophys. Acta 1529, 49-62, (2000). View articlePMID: 11111077

7.Biosynthesis of carotenoids in plastids of plants. Ladygin VG. Biochemistry Mosc. 65, 1113-28, (2000). PMID: 11092953

8.Genetics of eubacterial carotenoid biosynthesis: a colorful tale. Armstrong GA. Annu. Rev. Microbiol. 51, 629-59, (1997). View articlePMID: 9343362

9.Isoprenyl diphosphate synthases. Wang KC, Ohnuma S. Biochim. Biophys. Acta 1529, 33-48, (2000). View articlePMID: 11111076

GO terms

biological process

  • None

cellular component

  • None

Cross References

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