F. prausnitzii Heterologous Expression Feasibility (comp-008)¶
Frozen analysis archived at
etc/experiments/comp-008-f-prausnitzii-heterologous-expression/wiki-archive.md. Reproducible artifact:python3 etc/experiments/comp-008-f-prausnitzii-heterologous-expression/analyze.py.
Headline ranking¶
| Rank | Payload | Composite (base) | Range | Verdict | Limiting factor |
|---|---|---|---|---|---|
| 1 | Butyrate-pathway boost (native BCoAT, UniProt C7H5K4) | 0.748 | [0.641, 0.822] | GREEN | engineering toolkit maturity |
| 2 | sCR1 SCR1-4 truncation (UniProt P17927) | 0.565 | [0.433, 0.678] | YELLOW | engineering toolkit maturity |
| 3 | Human lactoferrin (UniProt P02788) | 0.540 | [0.423, 0.659] | YELLOW | engineering toolkit maturity |
| 4 | A. flavus uricase (UniProt Q00511) | 0.393 | [0.271, 0.523] | YELLOW (toward RED) | host physiology (O2 substrate vs strict anaerobe) |
Key findings¶
- Butyrate-pathway boost wins decisively. It is the only GREEN payload at the base score and remains GREEN with the engineering-toolkit gap excluded (toolkit-conditional score 0.875). CAI=1.0 (native gene), no secretion, no folding burden, native pathway alignment.
- Uricase is the wrong payload for this chassis. Uricase catalyzes uric acid + O2 → 5-hydroxyisourate + H2O2 (UniProt Q00511; verified 2026-05-16). F. prausnitzii is a strict obligate anaerobe in an anoxic colonic lumen. Even with a perfect engineering toolkit, the chemistry can't run. Strategic reclassification: uricase belongs on koji or E. coli Nissle (facultative anaerobe), not F. prausnitzii.
- Lactoferrin and sCR1 are conditional-GREEN candidates. Both have favorable host-physiology fit, both bottleneck on the same anoxic-environment-disulfide-folding question (lactoferrin 17 disulfides, sCR1 SCR1-4 8 disulfides). Mitigatable via heterologous DsbA/DsbB co-expression but not yet validated experimentally.
- The engineering-toolkit gap (0.25 across all payloads) is the gating factor. As of 2026-05, F. prausnitzii has no published transformation protocol. The 2023 Sheridan review of gut-bacteria genetic manipulation covers Bifidobacterium, Bacteroides, Roseburia, E. rectale — not F. prausnitzii. The literature workaround: MAM (F. prausnitzii's anti-inflammatory effector protein) is delivered to mouse gut via Lactococcus lactis carrying the plasmid (Quévrain 2016; Breyner 2017) — researchers engineered L. lactis, not F. prausnitzii. Closest engineering precedent for adapting a toolkit: Roseburia inulinivorans conjugation (Sheridan 2019 Anaerobe doi:10.1016/j.anaerobe.2019.06.008; Sheridan 2020 Bio Protoc doi:10.21769/BioProtoc.3575) — Lachnospiraceae phylogenetic neighbor, conjugative-transposon-based, 10⁻⁴ to 10⁻⁶ transconjugants/recipient. Estimated 1-2 yr to adapt to F. prausnitzii A2-165.
Codon / GC / secretion summary¶
- Genome: 2.78-3.23 Mbp, 56.6% GC (Fraccascia 2022 doi:10.1128/mra.00824-22). A2-165 = JCM 31915 = DSM 17677, reclassified as F. duncaniae by Sakamoto 2022.
- GC match: human payloads ~58% GC ↔ Fp 56.6% — only 1.4 pp mismatch, best of any chassis in the LBP track (vs Bacteroides 43%, EcN 51%). A. flavus uricase ~52% GC, 4-5 pp mismatch. Codon-optimization low-cost ($1-5K/cassette).
- Secretion: Sec-translocon (SecA/Y/E) + Tat-translocon (TatABC) both annotated. Native MAM secretion documented (Quévrain 2016). Heterologous-payload secretion titers never measured.
Cross-reference for engineered-lbp-chassis Phase 2¶
This comp informs / decides:
- P2-4 (this comp): complete; Fp engineering-naive as of 2026-05; Phase 2 should prioritize toolkit development BEFORE payload selection. P2-6 (chassis matrix): uricase belongs on EcN or koji; butyrate-boost belongs on Fp; lactoferrin / sCR1 routable to Fp or Bacteroides pending disulfide-folding investigation.
- Wet-lab sequence (if committed): (1) adapt Sheridan 2019 Lachnospiraceae conjugation toolkit, (2) chromosomally boost native BCoAT, (3) heterologously secrete a small reporter (e.g. NanoLuc) via Sec, (4) only then attempt lactoferrin / sCR1.
- comp-007 cross-link: butyrate was the top food-grade HDAC inhibitor by isoform selectivity (167× class-I over HDAC6). Continuous gut-luminal butyrate from engineered Fp solves oral bioavailability — comp-008 says it's the FIRST plausible engineering campaign in this chassis.