petB

Gene Description

Chloroplast cytochrome b6 subunit of the cytochrome b6f complex, supporting electron transfer between photosystem II and photosystem I in the thylakoid membrane.

Core Functions

Provides the cytochrome b6 electron-transfer subunit of the cytochrome b6f complex, linking PSII-derived plastoquinol oxidation to PSI electron donation.

Molecular Function:

heme binding

Directly Involved In:

photosynthetic electron transport chain

Cellular Locations:

chloroplast thylakoid membrane

In Complex:

cytochrome b6f complex

Supporting Evidence:

file:MISSI/petB/petB-uniprot.txt
Component of the cytochrome b6-f complex, which mediates electron transfer between photosystem II (PSII) and photosystem I (PSI), cyclic electron flow around PSI, and state transitions.
file:MISSI/petB/petB-uniprot.txt
Binds 2 heme b groups non-covalently with two histidine residues as axial ligands.

References

file:MISSI/petB/petB-uniprot.txt

UniProtKB entry for Miscanthus sinensis petB

UniProt describes PetB as cytochrome b6 in the cytochrome b6f complex, mediating electron transfer between PSII and PSI and binding heme b groups.

Suggested Experiments

Experiment: Measure cytochrome b6f content, plastoquinone redox state, and PSI/PSII electron flow under fluctuating light.

Type: targeted functional assay

📚 Additional Documentation

Notes

(petB-notes.md)

Curation notes

QuickGO export is header-only; therefore no UniProt DR/InterPro/HAMAP-derived terms are listed as existing_annotations or proposed as NEW.
Core function identifies cytochrome b6f electron transfer rather than generic photosynthesis or respiratory electron transport.
Addressed review suggestion: heme binding is recorded as the direct molecular function, while electron transfer activity is recorded as the complex-level contribution.