Subsystem: Isoprenoid Biosynthesis

This subsystem's description is:

Major terpenoid building blocks, isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP), are produced via two different biosynthetic routes: in some species by the so-called mevalonate pathway, and in others by the non-mevalonate or DOXP pathway. Both pathways produce the same key building blocks (IPP and DMAPP), essential in all forms of cellular life. They have apparently involved completely independently, and they share only one enzyme Isopentenyl-diphosphate delta-isomerase (IPDDI). Historically the mevalonate pathway and its enzymes were thoroughly studied in eukaryotes. Some bacteria also use mevalonate pathway, and all of the corresponding genes were identified based on homology with eukaryotic counterparts [Ref.2,3]. Although usually bacteria have only one of the two pathways, there are exceptions: Listeria has boths. Plants also have both, but one of them (DOXP) is of plastid (bacterial) origin. All other eukaryotes and archaea appear to have only mevalonate pathway. ISPC seems to be a missing gene in Brucella ssp. Reconstruction of the mevalonate pathway in archaea including conjectures for some locally missing genes was described [Ref.4]. The alternative DOXP pathway, characteristic of most bacteria was not recognized until very recently (for a review see [Ref.5]), and some aspects of it remained obscure until recently [Ref.6,7].

========= Variant codes:=================

Functional variants will be classified using the first discriminative number:

1.0 - mevalonate pathway
2.0 - non-mevalonate pathway
3.0 - both (mevalonate + non-mevalonate) pathways
-1 - none
0 - to be looked at

Anywhere after the dot in the number:
"9" - missing (but required) genes;
"8" - absentees (not required).


2.8: nonmevalonate pway without IPDDI (optional; as in prochlorococci)
2.9: nonmevalonate pway with a missing required gene (mostly sequencing, ORF-calling. annotation errors)
1.8: mevalonate patwhay without ACAT: Acetoacetyl-CoA may come from a difference source (eg see Leu-deg susbsystem)

For more information, please check out the description and the additional notes tabs, below

Literature ReferencesIdentification, evolution, and essentiality of the mevalonate pathway for isopentenyl diphosphate biosynthesis in gram-positive cocci. Wilding EI Journal of bacteriology 2000 Aug10894743
Missing genes in metabolic pathways: a comparative genomics approach. Osterman A Current opinion in chemical biology 2003 Apr12714058
DiagramFunctional RolesSubsystem SpreadsheetDescriptionAdditional NotesScenarios 

Showing colors for genome: Chloroflexus aurantiacus J-10-fl ( 324602.4 ), variant code 1.0

This diagram has been scaled to 72.99%.  

Group Alias
Abbrev.Functional RoleReactionsScenario ReactionsGOLiterature

display  items per page
«first  «prevdisplaying 1 - 2982 of 2982next»  last»
Taxonomy Pattern