KEGG   PATHWAY: mhk00720
Entry
mhk00720                    Pathway                                
Name
Other carbon fixation pathways - Metallosphaera hakonensis JCM 8857 = DSM 7519
Description
Carbon fixation is an important pathway for autotrophs living in various environments. Plants and cyanobacteria fix CO2 as organic compounds using solar energy mainly by the reductive pentose phosphate cycle (also called Calvin cycle, Calvin-Benson cycle, or Calvin-Benson-Bassham cycle) [MD:M00165]. There are, at least, five additional carbon fixation pathways known to exist in autotrophic bacteria and archaea, which differ in reducing compounds, energy source, and oxygen sensitivity of enzymes. (i) The reductive citric acid cycle (Arnon-Buchanan cycle) [MD:M00173] is found in microaerophiles and anaerobes, such as green sulfur bacteria. In one complete turn of this cycle, four molecules of CO2 are fixed by the enzymes that are sensitive to oxygen, resulting in the production of one molecule of oxaloacetate, which is itself an intermediate of the cycle. (ii) The reductive acetyl-CoA pathway (Wood-Ljungdahl pathway) [MD:M00377] is found in strictly anaerobic bacteria and archaea (Proteobacteria, Planctomycetes, Spirochaetes, and Euryarchaeota), some of which are methane-forming. A bifunctional enzyme, carbon monoxide dehydrogenase/acetyl-CoA synthase, catalyzes the reactions from CO2 to CO and from CO2 to a methyl group, and then to generate acetyl-CoA. (iii) The 3-hydroxypropionate bicycle [MD:M00376] is found in some green non-sulphur bacteria of the family Chloroflexaceae. In one complete turn of this bicycle, three molecules of bicarbonate are converted into one molecule of pyruvate. In addition, this bicycle provides the secondary benefit of useful intermediates for biosynthesis: acetyl-CoA, glyoxylate, and succinyl-CoA. (iv) The hydroxypropionate-hydroxybutyrate cycle [MD:M00375] is found in aerobic Crenarchaeota, Acidianus, Metallosphaera, and Sulfolobales. Some of the intermediates and the carboxylation reactions are the same as in the 3-hydroxypropionate bicycle. One complete turn of this cycle generates two molecules of acetyl-CoA, one of which is reutilized in the the cycle and the other is removed for cell material biosynthesis. (v) The dicarboxylate-hydroxybutyrate cycle [MD:M00374] was named after its intermediates: succinate (a kind of dicarboxylate) and hydroxybutyrate. This cycle has been found only in Ignicoccus hospitals, a strictly anaerobic hyperthermophilic archaea. Recent genome study suggests that this cycle may exist in Desulfurococcales (to which Ignicoccus belongs) and Thermoproteales (a taxon close to the origin of archaea). The first half of the cycle, from acetyl-CoA to succinate-CoA, corresponds to the reductive citric acid cycle and the latter half of the cycle, from succinate-CoA to two molecules of acetyl-CoA, corresponds to the hydroxypropionate-hydroxybutyrate cycle.
Class
Metabolism; Energy metabolism
Pathway map
mhk00720  Other carbon fixation pathways
mhk00720

Module
mhk_M00374  Dicarboxylate-hydroxybutyrate cycle [PATH:mhk00720]
mhk_M00375  Hydroxypropionate-hydroxybutylate cycle [PATH:mhk00720]
Other DBs
GO: 0015977
Organism
Metallosphaera hakonensis JCM 8857 = DSM 7519 [GN:mhk]
Gene
DFR87_04615  pyruvate ferredoxin oxidoreductase [KO:K00169] [EC:1.2.7.1]
DFR87_05210  pyruvate ferredoxin oxidoreductase [KO:K00169] [EC:1.2.7.1]
DFR87_04620  pyruvate synthase subunit beta [KO:K00170] [EC:1.2.7.1]
DFR87_05205  3-methyl-2-oxobutanoate dehydrogenase subunit beta [KO:K00170] [EC:1.2.7.1]
DFR87_05220  pyruvate synthase [KO:K00172] [EC:1.2.7.1]
DFR87_04605  pyruvate synthase [KO:K00172] [EC:1.2.7.1]
DFR87_04610  4Fe-4S dicluster domain-containing protein [KO:K00171] [EC:1.2.7.1]
DFR87_05215  4Fe-4S dicluster domain-containing protein [KO:K00171] [EC:1.2.7.1]
DFR87_04040  pyruvate, water dikinase [KO:K01007] [EC:2.7.9.2]
DFR87_10200  ppsA; pyruvate, water dikinase [KO:K01007] [EC:2.7.9.2]
DFR87_03645  phosphoenolpyruvate carboxylase [KO:K01595] [EC:4.1.1.31]
DFR87_03910  malate dehydrogenase [KO:K00024] [EC:1.1.1.37]
DFR87_12130  fumarate hydratase [KO:K01677] [EC:4.2.1.2]
DFR87_12135  Fe-S hydro-lyase subunit beta [KO:K01678] [EC:4.2.1.2]
DFR87_11430  fumarate hydratase [KO:K01679] [EC:4.2.1.2]
DFR87_03130  succinate dehydrogenase flavoprotein subunit [KO:K00239] [EC:1.3.5.1]
DFR87_12140  FAD-binding protein [KO:K00239] [EC:1.3.5.1]
DFR87_03125  succinate dehydrogenase/fumarate reductase iron-sulfur subunit [KO:K00240] [EC:1.3.5.1]
DFR87_12155  sdhB; succinate dehydrogenase iron-sulfur subunit [KO:K00240] [EC:1.3.5.1]
DFR87_03120  disulfide reductase [KO:K00241]
DFR87_12145  succinate dehydrogenase [KO:K00241]
DFR87_12150  succinate dehydrogenase [KO:K00242]
DFR87_03115  succinate dehydrogenase [KO:K18859]
DFR87_10785  sucD; succinate--CoA ligase subunit alpha [KO:K01902] [EC:6.2.1.5]
DFR87_10790  succinate--CoA ligase subunit beta [KO:K01903] [EC:6.2.1.5]
DFR87_12125  aldehyde dehydrogenase family protein [KO:K15038] [EC:1.2.1.76]
DFR87_09790  aldehyde dehydrogenase family protein [KO:K15038] [EC:1.2.1.76]
DFR87_11755  alcohol dehydrogenase catalytic domain-containing protein [KO:K14465] [EC:1.1.1.-]
DFR87_04145  AMP-binding protein [KO:K14466] [EC:6.2.1.40]
DFR87_11765  phenylacetate--CoA ligase family protein [KO:K18861] [EC:6.2.1.40]
DFR87_04415  AMP-binding protein [KO:K25774] [EC:6.2.1.40]
DFR87_12060  4-hydroxybutyryl-CoA dehydratase [KO:K14534] [EC:4.2.1.120 5.3.3.3]
DFR87_04185  3-hydroxyacyl-CoA dehydrogenase [KO:K15016] [EC:4.2.1.17 1.1.1.35]
DFR87_04390  3-hydroxyacyl-CoA dehydrogenase family protein [KO:K15016] [EC:4.2.1.17 1.1.1.35]
DFR87_11760  3-hydroxyacyl-CoA dehydrogenase [KO:K15016] [EC:4.2.1.17 1.1.1.35]
DFR87_03020  acetyl-CoA C-acyltransferase [KO:K00626] [EC:2.3.1.9]
DFR87_04160  thiolase domain-containing protein [KO:K00626] [EC:2.3.1.9]
DFR87_04375  thiolase domain-containing protein [KO:K00626] [EC:2.3.1.9]
DFR87_05445  thiolase domain-containing protein [KO:K00626] [EC:2.3.1.9]
DFR87_05450  thiolase domain-containing protein [KO:K00626] [EC:2.3.1.9]
DFR87_10455  thiolase family protein [KO:K00626] [EC:2.3.1.9]
DFR87_12260  thiolase family protein [KO:K00626] [EC:2.3.1.9]
DFR87_04800  2-oxoacid:acceptor oxidoreductase subunit alpha [KO:K00174] [EC:1.2.7.3 1.2.7.11]
DFR87_04795  2-oxoacid:ferredoxin oxidoreductase subunit beta [KO:K00175] [EC:1.2.7.3 1.2.7.11]
DFR87_03270  NADP-dependent isocitrate dehydrogenase [KO:K00031] [EC:1.1.1.42]
DFR87_11400  acnA; aconitate hydratase AcnA [KO:K01681] [EC:4.2.1.3]
DFR87_06075  acetyl-CoA carboxylase biotin carboxylase subunit [KO:K01964] [EC:6.4.1.2 6.4.1.3]
DFR87_11880  methylmalonyl-CoA carboxyltransferase [KO:K15036] [EC:6.4.1.2 6.4.1.3 2.1.3.15]
DFR87_06070  biotin/lipoyl-binding protein [KO:K15037]
DFR87_03300  asd; aspartate-semialdehyde dehydrogenase [KO:K15017] [EC:1.2.1.75 1.2.1.76]
DFR87_08540  3-hydroxyacyl-CoA dehydrogenase family protein [KO:K15039] [EC:1.1.1.298]
DFR87_11465  acs; acetate--CoA ligase [KO:K15018] [EC:6.2.1.36]
DFR87_08490  crotonase [KO:K15019] [EC:4.2.1.116]
DFR87_11745  alcohol dehydrogenase catalytic domain-containing protein [KO:K15020] [EC:1.3.1.84]
DFR87_02925  mce; methylmalonyl-CoA epimerase [KO:K05606] [EC:5.1.99.1]
DFR87_02920  methylmalonyl-CoA mutase [KO:K01848] [EC:5.4.99.2]
DFR87_08210  methylmalonyl-CoA mutase [KO:K01849] [EC:5.4.99.2]
DFR87_12270  AMP-binding protein [KO:K01895] [EC:6.2.1.1]
DFR87_12345  acs; acetate--CoA ligase [KO:K01895] [EC:6.2.1.1]
DFR87_05465  AMP-binding protein [KO:K01895] [EC:6.2.1.1]
Compound
C00011  CO2
C00022  Pyruvate
C00024  Acetyl-CoA
C00026  2-Oxoglutarate
C00033  Acetate
C00036  Oxaloacetate
C00042  Succinate
C00048  Glyoxylate
C00058  Formate
C00074  Phosphoenolpyruvate
C00083  Malonyl-CoA
C00091  Succinyl-CoA
C00100  Propanoyl-CoA
C00101  Tetrahydrofolate
C00122  Fumarate
C00143  5,10-Methylenetetrahydrofolate
C00149  (S)-Malate
C00158  Citrate
C00222  3-Oxopropanoate
C00227  Acetyl phosphate
C00232  Succinate semialdehyde
C00234  10-Formyltetrahydrofolate
C00237  CO
C00288  HCO3-
C00311  Isocitrate
C00332  Acetoacetyl-CoA
C00417  cis-Aconitate
C00440  5-Methyltetrahydrofolate
C00445  5,10-Methenyltetrahydrofolate
C00566  (3S)-Citryl-CoA
C00683  (S)-Methylmalonyl-CoA
C00877  Crotonoyl-CoA
C00894  Propenoyl-CoA
C00989  4-Hydroxybutanoic acid
C01011  (3S)-Citramalyl-CoA
C01013  3-Hydroxypropanoate
C01144  (S)-3-Hydroxybutanoyl-CoA
C01213  (R)-Methylmalonyl-CoA
C04348  L-Malyl-CoA
C05668  3-Hydroxypropionyl-CoA
C06027  L-erythro-3-Methylmalyl-CoA
C06028  2-Methylfumaryl-CoA
C11062  4-Hydroxybutyryl-CoA
C18323  3-Methylfumaryl-CoA
Reference
  Authors
Zarzycki J, Brecht V, Muller M, Fuchs G
  Title
Identifying the missing steps of the autotrophic 3-hydroxypropionate CO2 fixation cycle in Chloroflexus aurantiacus.
  Journal
Proc Natl Acad Sci U S A 106:21317-22 (2009)
DOI:10.1073/pnas.0908356106
Reference
  Authors
Teufel R, Kung JW, Kockelkorn D, Alber BE, Fuchs G
  Title
3-hydroxypropionyl-coenzyme A dehydratase and acryloyl-coenzyme A reductase, enzymes of the autotrophic 3-hydroxypropionate/4-hydroxybutyrate cycle in the Sulfolobales.
  Journal
J Bacteriol 191:4572-81 (2009)
DOI:10.1128/JB.00068-09
Reference
  Authors
Huber H, Gallenberger M, Jahn U, Eylert E, Berg IA, Kockelkorn D, Eisenreich W, Fuchs G
  Title
A dicarboxylate/4-hydroxybutyrate autotrophic carbon assimilation cycle in the hyperthermophilic Archaeum Ignicoccus hospitalis.
  Journal
Proc Natl Acad Sci U S A 105:7851-6 (2008)
DOI:10.1073/pnas.0801043105
Reference
  Authors
Hugler M, Wirsen CO, Fuchs G, Taylor CD, Sievert SM
  Title
Evidence for autotrophic CO2 fixation via the reductive tricarboxylic acid cycle by members of the epsilon subdivision of proteobacteria.
  Journal
J Bacteriol 187:3020-7 (2005)
DOI:10.1128/JB.187.9.3020-3027.2005
Reference
  Authors
Seravalli J, Kumar M, Ragsdale SW
  Title
Rapid kinetic studies of acetyl-CoA synthesis: evidence supporting the catalytic intermediacy of a paramagnetic NiFeC species in the autotrophic Wood-Ljungdahl pathway.
  Journal
Biochemistry 41:1807-19 (2002)
DOI:10.1021/bi011687i
Reference
PMID:3096193
  Authors
Ljungdahl LG
  Title
The autotrophic pathway of acetate synthesis in acetogenic bacteria.
  Journal
Annu Rev Microbiol 40:415-50 (1986)
DOI:10.1146/annurev.mi.40.100186.002215
Related
pathway
mhk00710  Carbon fixation by Calvin cycle
KO pathway
ko00720   
LinkDB

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