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Calvin-Benson-Bassham cycle

traitmech:000020 · CLASS · REVIEWED

An autotrophic carbon-fixation pathway (the reductive pentose phosphate cycle) that fixes CO2 using ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO). It is the most widespread CO2-fixation pathway, used by plants, algae, cyanobacteria, and many proteobacteria.

Calvin-Benson-Bassham cycle fixes CO2 via RuBisCO

Evidence-backed causal sketch linking RuBisCO-catalyzed CO2 carboxylation of RuBP to the reductive pentose phosphate cycle.

Calvin-Benson-Bassham cycle fixes CO2 via RuBisCO Interactive directed graph showing evidence-backed causal relationships for Calvin-Benson-Bassham cycle.

Edge evidence

  • RuBisCO enables Calvin-Benson cycle RO:0002327

    RuBisCO catalyzes the CO2-fixing carboxylation step of the cycle.

    • DOI:10.1128/AEM.02473-10 Berg identifies the CBB cycle as the reference autotrophic pathway.
  • Calvin-Benson cycle enables Calvin-Benson-Bassham cycle RO:0002327

    The reductive pentose phosphate cycle realizes the trait.

    • DOI:10.1146/annurev-marine-120709-142712 Hügler & Sievert support the Calvin cycle as the most widespread CO2-fixation pathway.
  • carbon dioxide fixed by Calvin-Benson-Bassham cycle METPO:2007404

    CO2 is the substrate fixed by the CBB cycle.

    • DOI:10.1128/AEM.02473-10 Berg identifies the CBB cycle as a CO2-fixing pathway.
  • RuBisCO converts 3-phospho-D-glycerate

    RuBisCO catalyzes the first CBB reaction, carboxylating RuBP with CO2 to yield 3-phosphoglycerate.

    • DOI:10.1111/ppl.14140 Kurkela 2024: "RubisCo... catalyses the first CBB reaction (RuBP + CO2 -> 3-PGA)."
  • ribulose-1,5-bisphosphate substrate of RuBisCO

    RuBP is the CO2-acceptor substrate carboxylated by RuBisCO.

    • DOI:10.1111/ppl.14140 Kurkela 2024: RuBP + CO2 -> 3-PGA is the first CBB reaction catalysed by RubisCo.
  • carboxysome contains RuBisCO

    Carboxysomes encapsulate RuBisCO as part of the CO2-concentrating mechanism.

    • DOI:10.1111/ppl.14140 Kurkela 2024: "carboxysomes that encapsulate RuBisCo and carbonic anhydrase."
  • carboxysome concentrates carbon dioxide

    Carboxysomes concentrate CO2 near RuBisCO, bridging environmental DIC supply to enzymatic demand.

    • DOI:10.1128/AEM.01557-23 Scott 2024: "carboxysomes... concentrate CO2 near Rubisco to bridge environmental DIC supply to enzymatic demand."
  • carboxysomal carbonic anhydrase converts carbon dioxide

    Carboxysomal carbonic anhydrase converts HCO3- to CO2 to elevate luminal CO2 and promote RuBisCO fixation.

    • DOI:10.1126/sciadv.adk7283 Pulsford 2024: within carboxysomes, CA converts HCO3- to CO2 to elevate luminal CO2 and promote Rubisco-catalyzed CO2 fixation.
  • bicarbonate substrate of carboxysomal carbonic anhydrase

    Bicarbonate is dehydrated by carboxysomal carbonic anhydrase to supply CO2 to RuBisCO.

    • DOI:10.1126/sciadv.adk7283 Pulsford 2024: carboxysomal CA converts HCO3- to CO2 to promote Rubisco-catalyzed CO2 fixation.
  • CbbR transcriptional regulator activates transcription of cbb operon

    CbbR is the master transcriptional activator that elevates expression of bacterial cbb CO2-fixation operons.

    • DOI:10.1128/JB.00442-15 Dangel 2015: "CbbR, the Master Regulator for Microbial Carbon Dioxide Fixation"; elevates expression of the cbb CO2 fixation operons. Broad evidence across bacteria.
  • cytoplasmic carbonic anhydrase can cause CO2 leakage

    Cytosolic (non-vectorial) carbonic anhydrase activity can dissipate the CCM by causing CO2 leakage.

    • DOI:10.1128/AEM.01557-23 Scott 2024: "cytosolic (non-vectoral) CA activity can dissipate the CCM by causing CO2 leakage."

Provenance

Source
METPO (2025-11-25)
Definition source
DOI:10.1128/AEM.02473-10

Parent traits (1)

Synonyms (2)

  • Calvin cycle EXACT_SYNONYM · DOI:10.1128/AEM.02473-10
  • reductive pentose phosphate cycle RELATED_SYNONYM · DOI:10.1128/AEM.02473-10

kg-microbe context

Matched 1 kg-microbe node via parent_proxy.

  • METPO:1000060 [-1.052, -1.766, -1.194, +0.291, …]

512-dim DeepWalkSkipGramEnsmallen embedding from kg-microbe (2026-04-25).

Nearest neighbors in embedding space

Top-8 cosine-similar METPO traits from the 2026-04-25 deepwalk (512-D).

Curation history

  1. · PROPOSED_FROM_RESEARCH · claude

    Proposed candidate METABOLISM trait (Calvin-Benson-Bassham carbon-fixation cycle); sub-variant of carbon fixation.

  2. · CURATED_CAUSAL_GRAPH · claude

    Added evidence-backed causal graph (CBB / RuBisCO CO2 fixation) with CHEBI/GO node groundings and RO/METPO predicate groundings; promoted PROPOSED to REVIEWED.

  3. · GROUND_CAUSAL_NODES · claude

    Grounded 1 causal-node grounding field(s) via mappings/node_grounding.tsv (UniProtKB:A0A075WF79×1).

  4. · ENRICH_CAUSAL_GRAPH · claude

    Added 8 evidence-backed generic edges (9 new nodes) from the deep-research report.

  5. · GROUND_CAUSAL_NODES · claude

    Grounded 3 causal-node grounding field(s) via mappings/node_grounding.tsv (CHEBI:17794×1, GO:0031470×1, CHEBI:17544×1).