pe
pep-05201 v1 CC-BY-SA-4.0

Microcin H47 cancer-fighting peptide

An experimental peptide studied for its ability to attack cancer cells; not an approved drug.

statusbioassayed targetANTICANCER length60 aa refs1
anticancer
EARLY ENTRY This candidate is newly indexed — supporting evidence is still being added. Have a paper or data point? Contribute below.
status 2 / 5 · 0 verified on platform
prediction metrics boltz-2 2.2.1
ipTM0.000
pTM0.448
avg pLDDT64.3
ranking score0.604
STRUCTURE · PEP-05201 × ANTICANCER
ranking0.604
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RECEPTOR UNKNOWN
peptide conformation only · no target structure
target interface 4.5Å peptide drag rotate · ctrl+scroll zoom · right-click pan
sequence60 aa
151015202530354045505560
GGAPATSANAAGAAAIVGAL AGIPGGPLGVVVGAVSAGLT TAIGSTVGSGSASSSAGGGS
in the news 27 articles
Hypotheses3 directions▾ collapse

Research directions for this peptide, selected from the current sources — hypotheses you can explore and model. None of it is proven yet; tap any one to see the full thinking.

openupdated 2026-06-11

Has anyone identified the actual molecule this peptide acts on inside a cancer cell, or is 'anticancer' just shorthand for 'kills cells in a dish'?

This matters for anyone trying to improve or combine this peptide. Microcin H47 is a known antibacterial peptide that works by sneaking through bacterial iron-uptake channels and blocking the cell's ATP synthase, so its 'anticancer' tag may be an unvalidated screening result with no human target behind it.

The hypothesis
The annotated target 'anticancer' is a phenotypic label rather than a molecular target, and Microcin H47's actual molecular counterpart is likely the bacterial FtsH/ATP-dependent inner-membrane protease homolog present in the original E. coli context, with anticancer activity being a secondary off-target effect discovered in phenotypic screens.
Why it’s plausible
MccH47 is a ribosomally synthesized bacteriocin active against gram-negative bacteria. The mchB gene literature establishes biosynthetic requirements but not a eukaryotic target. The sequence has no features (RGD motif, integrin-binding loops, receptor-binding beta-turns) expected of a peptide evolved to bind mammalian receptors. 'Anticancer' annotations in peptide databases frequently reflect IC50 data from cell-viability screens, not validated receptor binding.
Why it matters
Clarifying that no eukaryotic molecular target has been validated would redirect development toward either identifying the actual mammalian binding partner or repositioning the peptide toward microbiome-mediated tumor suppression, where its bacteriocin activity is on-mechanism.
Plausibility.78
Novelty.50
Impact.78
Basis · grounding1 paper · 2 computed/notes
[1]
paper
The only literature snippet addresses biosynthesis (mchB gene requirement), with no mention of eukaryotic targets or anticancer mechanism.
doi: 10.1128/aac.43.9.2176
[2]
sequenceNo canonical eukaryotic receptor-binding motifs (RGD, NGR, integrin-binding loops) are present in the 60-aa sequence.
[3]
structureipTM is None (no complex prediction computed), consistent with absence of a known molecular partner to dock against.
openupdated 2026-06-11

Could this antibacterial peptide reduce the gut bacteria linked to colorectal cancer, offering an indirect benefit rather than directly killing tumor cells?

If true, it could be delivered to the gut rather than injected, a simpler path. One caveat: this peptide's natural killing range is fairly narrow, so whether it actually hits cancer-linked bacteria like Fusobacterium would need to be tested before any claim of benefit.

The hypothesis
Microcin H47 could suppress tumor-promoting gut bacteria (e.g., Fusobacterium nucleatum or Peptostreptococcus anaerobius) in colorectal cancer patients, providing an indirect anticancer benefit through microbiome modulation rather than direct tumor cell killing.
Why it’s plausible
MccH47 is a gram-negative-targeting bacteriocin with defined biosynthesis. Several colorectal cancer-associated pathogens are gram-negative anaerobes for which MccH47-family peptides may have activity. Its biosynthetic gene cluster is self-contained (mch genes), suggesting it could be delivered as a live-biotherapeutic or recombinant agent to the gut without requiring systemic absorption.
Why it matters
Microbiome-driven colorectal carcinogenesis is a clinically actionable target and oral bacteriocins face a much lower regulatory and delivery barrier than systemic peptide drugs. If MccH47 hits tumor-promoting microbes, it connects an established bacteriocin to a precision oncology application without needing to fix its poorly supported direct anticancer mechanism.
Plausibility.55
Novelty.60
Impact.65
Basis · grounding1 paper · 1 computed/note
[1]
paper
MccH47 is a gram-negative-active bacteriocin; mchB is required for synthesis, establishing it as a genuine antimicrobial agent targeting gram-negative bacteria.
doi: 10.1128/aac.43.9.2176
[2]
sequenceThe hydrophobic pore-forming motifs are consistent with activity against gram-negative inner membranes, the compartment accessible to bacteriocins after outer-membrane translocation via the Ton-B system.
openupdated 2026-06-11

Could a trimmed core of this peptide keep its activity while being cheaper to make, or are the floppy ends actually required?

A shorter peptide would be far cheaper to produce. A caveat to test first: in natural Microcin H47 the serine-rich C-terminal region carries an essential chemical modification needed for activity, so simply cutting that end could abolish function rather than preserve it.

The hypothesis
The Gly/Ala/Ser-rich flanking regions of Microcin H47 (N-terminal GGAPATSANAAGAAA and C-terminal GSGSASSSAGGGS) function as intrinsically disordered solubility tags that could be truncated without abolishing pore-forming activity, yielding a shorter, more synthetically accessible core peptide (approximately residues 15-52) with retained membrane activity.
Why it’s plausible
Intrinsically disordered Gly/Ser-rich termini are common in bacteriocins as biosynthetic or export artifacts. The hydrophobic core is bracketed by ~14 aa of highly polar N-terminal and ~8 aa of polar C-terminal sequence, neither of which is expected to participate in membrane insertion. Truncating these regions would reduce the peptide from 60 to approximately 38 residues, cutting synthesis cost roughly 40% and potentially improving cell permeability.
Why it matters
Synthetic accessibility is the primary bottleneck for peptide drug development. If the flanking disordered regions are expendable, the active core becomes a viable synthetic candidate, enabling medicinal chemistry optimization that would be cost-prohibitive on the full 60-mer.
Plausibility.45
Novelty.45
Impact.55
Basis · grounding2 computed/notes
[1]
sequenceResidues 1-14 are GGAPATSANAAGAAA (all Gly/Ala/Ser/Thr/Asn, no hydrophobic contribution); residues 53-60 are GSASSSAGG (again pure polar/Gly). These 22 residues contribute no hydrophobic moment.
[2]
structurepLDDT 64.3 suggests these disordered terminal regions pull the overall confidence score down, consistent with their being unstructured appendages rather than functional domains.
details expand to inspect
full evidence table1 metrics
metricvaluetool
ranking score 0.6037186980247498 boltz-2
3-letter notation
Gly-Gly-Ala-Pro-Ala-Thr-Ser-Ala-Asn-Ala-Ala-Gly-Ala-Ala-Ala-Ile-Val-Gly-Ala-Leu-Ala-Gly-Ile-Pro-Gly-Gly-Pro-Leu-Gly-Val-Val-Val-Gly-Ala-Val-Ser-Ala-Gly-Leu-Thr-Thr-Ala-Ile-Gly-Ser-Thr-Val-Gly-Ser-Gly-Ser-Ala-Ser-Ser-Ser-Ala-Gly-Gly-Gly-Ser
recipeboltz-2 2.2.1
parametervalue
modelboltz-2 2.2.1
weights
hardwarevast_v100_32gb
mlx version
python
random seed1
msa strategynone_monomer
runtime
predicted by
predicted at2026-05-23
citationbibtex
peptidemodel (2026). Microcin H47 cancer-fighting peptide (pep-05201, v1). PeptideModel. https://peptidemodel.com/card/pep-05201
@peptide{pep05201,
  sequence = {GGAPATSANAAGAAAIVGALAGIPGGPLGVVVGAVSAGLTTAIGSTVGSGSASSSAGGGS},
  target   = {anticancer},
  author   = {peptidemodel},
  year     = {2026},
  status   = {bioassayed}
}
related peptides 1 by signal overlap
references 1 papers
[1]
The Structural Gene for Microcin H47 Encodes a Peptide Precursor with Antibiotic Activity
Rodríguez E; Gaggero C; Laviña M Antimicrobial Agents and Chemotherapy 1999
source scaffold
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