sdhD

Summary: Correct localization for the bacterial inner-membrane succinate dehydrogenase anchor subunit.

Reason: UniProt annotates SdhD as a cell inner membrane, multi-pass membrane protein. In Gram-negative bacteria the inner membrane corresponds to the GO plasma membrane.

Summary: Correct TCA-cycle annotation because SdhD is part of the SdhABCD succinate dehydrogenase complex.

Reason: The SdhABCD complex catalyzes the succinate-to-fumarate step of the TCA cycle. SdhD is not the catalytic flavoprotein subunit, but it is part of the required membrane anchor/quinone-transfer domain of the same complex.

Summary: Correct subunit-level role for the heme/quinone membrane domain of succinate dehydrogenase.

Reason: SdhD is a membrane anchor subunit with heme and ubiquinone-binding features, contributing to electron transfer from the catalytic head to the quinone pool.

Summary: Correct respiratory context for the forward succinate dehydrogenase complex.

Reason: SdhD is part of membrane-bound succinate dehydrogenase/Complex II, coupling TCA-cycle succinate oxidation to aerobic respiratory electron transfer.

Summary: Correct but less precise than the plasma membrane/inner membrane annotation.

Reason: SdhD is a membrane protein, but UniProt specifies the bacterial cell inner membrane and GOA already has the more informative plasma membrane annotation. Use GO:0005886 as the preferred location term.

Proposed replacements: plasma membrane

Summary: Over-propagated assembly-process annotation; SdhD is a cytochrome/heme-containing subunit, not an assembly factor.

Reason: Re-review: relaxed from REMOVE to MARK_AS_OVER_ANNOTATED. GO:0017004 is defined as the aggregation, arrangement and bonding together of a cytochrome complex. UniProt describes SdhD as the membrane-anchoring subunit of succinate dehydrogenase that binds heme together with the second transmembrane subunit, so it is a structural heme-ligating component of the cytochrome b556 module rather than a demonstrated assembly factor; for Complex II the accessory assembly role is attributed to SdhE. Being the thing assembled is not the same as doing the assembling, so the term attributes more than the evidence supports. It is flagged rather than removed because a structural subunit supplying the heme axial ligands does contribute to formation of its own cytochrome module, which cannot be excluded here.

Summary: Correct heme-binding feature for the SdhC/SdhD membrane anchor domain.

Reason: UniProt annotates heme for SdhD and states that the heme is bound between the two transmembrane subunits. This is a meaningful molecular feature of the Complex II membrane domain.