Small STAS-domain MlaB-like cytoplasmic subunit encoded with MlaF, MlaE, MlaD, and the Ttg2D/MlaC carrier. Ttg2E is assigned a structural or regulatory role in assembly and activity of the inner-membrane MlaFEDB phospholipid transport complex.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0120010 intermembrane phospholipid transfer | ISS file:PSEPK/ttg2E/ttg2E-deep-research-openscientist.md | NEW | Summary: Ttg2E is the MlaB-like accessory subunit of the MlaFEDB phospholipid-transfer complex. Reason: Its single STAS domain and mlaF-mlaE-mlaD-ttg2D-ttg2E operon position support the conserved MlaB role. |
| GO:0043190 ATP-binding cassette (ABC) transporter complex | ISS file:PSEPK/ttg2E/ttg2E-deep-research-openscientist.md | NEW | Summary: Ttg2E is a non-catalytic STAS accessory unit of MlaFEDB. Reason: MlaB orthologs bind the MlaF ATPase and support transporter assembly or activity; the exact KT2440 mechanism remains untested. |
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Download this section (compressed HTML)Q: How does Ttg2E affect KT2440 MlaFEDB assembly, stability, and MlaF ATPase coupling?
Experiment: Compare MlaFEDB assembly, ATPase activity, and phospholipid transfer with and without Ttg2E.
Type: complex reconstitution and subunit-omission assay
What is not known — curated, literature-grounded statements of the open unknowns (the inverse of core functions).
Gap: The exact effect of KT2440 Ttg2E on MlaFEDB assembly, stability, and MlaF ATPase activity is untested.
OPEN BIOLOGY
Significance: STAS architecture and operon position establish MlaB-equivalent identity, but no catalytic molecular function or precise regulatory mechanism is assigned.
Gap: Ttg2E has not been individually tested for solvent tolerance or envelope phenotypes in KT2440.
OPEN BIOLOGY
Significance: The historical toluene-tolerance name is pathway-level phenotype context, not a direct molecular-function annotation.
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Download this section (compressed HTML)Q88P90 is a 100-residue single-STAS-domain protein in the
mlaF-mlaE-mlaD-ttg2D-ttg2E locus. The report correctly recognizes this as the
diagnostic architecture and operon position of an MlaB-equivalent accessory
subunit [file:PSEPK/ttg2E/ttg2E-deep-research-openscientist.md, "This gene
order (F‑E‑D‑C‑B) is identical to the canonical E. coli mlaFEDCB operon,
unambiguously assigning ttg2E = MlaB."].
Ortholog studies support roles in transporter assembly and activity, but the
precise effect on KT2440 MlaF is untested. The review therefore assigns no
catalytic molecular function and retains the mechanism as a knowledge gap.
The report's retrograde-direction and direct toluene-tolerance language is not
promoted to a Ttg2E-specific annotation.
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