PP_0313 is the beta subunit of a heterodimeric electron-transfer flavoprotein (ETF) encoded immediately downstream of the DgcAB dimethylglycine dehydrogenase genes and next to the alpha-subunit gene PP_0312. It belongs to the ETF beta-subunit/FixA family. Together with the FAD-binding alpha subunit PP_0312, it is thought to carry reducing equivalents generated during dimethylglycine conversion to sarcosine. This assignment rests on conserved synteny and on genetics of the orthologous Chromohalobacter salexigens locus, not on biochemistry of the KT2440 proteins. KT2440 encodes a second, sequence-divergent ETF pair, PP_4201-PP_4202.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0009055 electron transfer activity | IEA GO_REF:0000120 | ACCEPT | Summary: Appropriate molecular function for an ETF beta subunit. Reason: Combined automated annotation (GO_REF:0000120) from the InterPro ETF beta-subunit family (IPR012255) mapping and PANTHER node PTN002327631 (PTHR21294, whose electron-transfer IBD sits on PTN007689635). Q88R21 also matches the Pfam ETF domain. Electron transfer between partner flavoenzymes and downstream acceptors is the defining function of the ETF heterodimer (PMID:8962055), and the 60.2%-identical Chromohalobacter ortholog EtfB is genetically required for dimethylglycine degradation (PMID:32631860). The UniProt SIMILARITY line is ARBA-only and is not cited. The beta subunit does not hold the FAD, so core_functions records the activity as contributes_to_molecular_function, as in the human ETFB review; the GOA term itself is correct. Supporting Evidence: file:PSEPK/PP_0313/PP_0313-uniprot.txt DR InterPro; IPR012255; ETF_b. file:PSEPK/PP_0313/PP_0313-uniprot.txt DR PANTHER; PTHR21294; ELECTRON TRANSFER FLAVOPROTEIN BETA-SUBUNIT; 1. PMID:8962055 They function as electron shuttles between primary flavoprotein dehydrogenases involved in mitochondrial fatty acid and amino acid catabolism and the membrane-bound electron transfer flavoprotein ubiquinone oxidoreductase. |
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Download this section (compressed HTML)Q: What respiratory-chain component accepts electrons from the PP_0312/PP_0313 ETF heterodimer?
Experiment: Reconstitute reduced DgcB with PP_0312/PP_0313 and candidate downstream acceptors while monitoring electron transfer.
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