pe
pep-05190 v1 CC-BY-SA-4.0

Anticancer peptide

A peptide studied in the lab for its potential to fight cancer cells; experimental, not yet an approved drug.

statuscomputed targetANTICANCER length60 aa refs3
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 · 2 contributors
prediction metrics boltz-2 2.2.1
ipTM0.000
pTM0.569
avg pLDDT79.4
ranking score0.749
STRUCTURE · PEP-05190 × ANTICANCER
ranking0.749
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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
MVTLVLLVFLLLNVVEDEAA SFPFSCPTLSGVCRKLCLPT EMFFGPLGCGKGFLCCVSHF
in the news 27 articles
Hypotheses6 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 2026-06-05

Could the same molecule that targets cancer cells also kill dangerous bacteria?

If this holds, a single drug candidate could potentially treat both tumors and bacterial infections, which is rare and would make it far more valuable to develop. This matters most for patients who face both challenges at once, such as those on immunosuppressive cancer therapy.

The hypothesis
pep-05190 retains antimicrobial activity against Gram-negative bacteria in addition to its anticancer tag, because the mature-region cysteine scaffold and cationic patch match the functional determinants of the omDB fish beta-defensins whose literature underpins this card.
Why it’s plausible
The provenance reference (doi 10.1016/j.molimm.2009.07.018) is not an anticancer paper at all: it characterizes rainbow trout beta-defensins (omDB-1 to omDB-3) as innate antimicrobial effectors induced upon bacterial challenge. The sequence of pep-05190 shares the six-cysteine spacing and signal-peptide architecture of that defensin family. If the mature peptide folds like omDB, it would be expected to disrupt bacterial outer membranes through the same cationic mechanism attributed to beta-defensins broadly. The anticancer label may have been applied because defensins cross-react with cancer cells, but the antimicrobial activity may be primary.
Why it matters
Confirming antimicrobial activity would double the utility of the molecule and suggest that a single scaffold could be developed as both an oncology and anti-infective agent, a rare and commercially attractive property.
Plausibility.83
Novelty.50
Impact.70
Basis · grounding1 paper · 1 computed/note
[1]
paper
The primary reference for this card characterizes omDB defensins as antimicrobials induced 16-fold in fish gut/gill by bacterial challenge, not as anticancer agents.
doi: 10.1016/j.molimm.2009.07.018
[2]
sequenceThe 6-cysteine framework and cationic patch are conserved features of beta-defensins that confer broad-spectrum antimicrobial activity across vertebrates.
openupdated 2026-06-05

Does this molecule destroy cancer cells by punching holes in their outer shell, instead of blocking a specific protein?

If cancer cells are killed by direct membrane rupture rather than by targeting a single protein, tumors could find it much harder to develop resistance, the way they often do against targeted drugs. That could mean longer-lasting treatment responses for patients.

The hypothesis
pep-05190 is a fish beta-defensin precursor whose mature form (approximately residues 26-60, CPTLSGVCRKLCLPTEMFFGPLGCGKGFLCCVSHF) kills cancer cells through cationic membrane disruption rather than receptor-mediated signaling.
Why it’s plausible
The N-terminal 20 residues (MVTLVLLVFLLLNVVEDEAA) are 75% hydrophobic, matching the canonical signal peptide of fish beta-defensin precursors as described in the omDB series of rainbow trout. The mature region contains a 6-cysteine scaffold with spacing 7-4-12-6-1, which matches the beta-defensin framework exactly and terminates in a CC doublet at positions 55-56 that is a structural hallmark of the defensin family. The cationic cluster RK at positions 34-35 and K at 51 in the full sequence would drive electrostatic attraction to the negatively charged phosphatidylserine-exposed outer leaflet of cancer cell membranes.
Why it matters
Establishing a membrane-lytic rather than receptor-mediated mechanism would explain the broad anticancer tag in the absence of any annotated target and would mean that resistance through target mutation is much less likely, a key advantage over kinase inhibitors.
Plausibility.75
Novelty.28
Impact.67
Basis · grounding2 papers · 1 computed/note
[1]
paper
Describes rainbow trout beta-defensins (omDB-1 to omDB-3) with three-exon gene organization and six-cysteine mature peptides; the literature hit that provenance-linked this card.
doi: 10.1016/j.molimm.2009.07.018
[2]
sequenceN-terminal MVTLVLLVFLLLNVVEDEAA is 75% hydrophobic, consistent with a signal peptide; mature region CPTLSGVCRKLCLPTEMFFGPLGCGKGFLCCVSHF carries 6 cysteines with spacing 7,4,12,6,1 and a terminal CC doublet, exactly matching the fish beta-defensin cysteine framework.
[3]
paper
Reviews anticancer peptide mechanisms including membrane disruption by cationic peptides as a primary mode of action.
doi: 10.1016/j.cbi.2022.110194
openupdated 2026-06-05

Would this molecule attack cancer cells without damaging the healthy tissue around them?

Many membrane-attacking cancer drugs cause collateral damage to normal cells. If this peptide's tightly folded shape limits that collateral damage, it could offer a wider margin between the dose that works and the dose that causes side effects, making it safer to use in practice.

The hypothesis
pep-05190 has substantially lower toxicity toward normal epithelial cells than toward cancer cells because the three-disulfide cysteine scaffold reduces non-specific membrane intercalation into zwitterionic phosphatidylcholine bilayers characteristic of healthy cells.
Why it’s plausible
Unstructured cationic peptides can insert nonspecifically into any membrane, causing broad cytotoxicity. The beta-defensin-like cysteine framework of pep-05190 constrains backbone flexibility, which raises the energetic cost of the conformational change needed to insert into tightly packed zwitterionic bilayers (normal cells) while retaining the ability to bind loosely ordered, phosphatidylserine-enriched regions. Beta-defensins in the fish innate immune system demonstrate selective activity against microbes without gross host toxicity, suggesting the scaffold itself encodes selectivity.
Why it matters
A narrow therapeutic window is the main clinical obstacle for membrane-lytic anticancer peptides. Demonstrating that the disulfide scaffold reduces off-target membrane activity would make pep-05190 a more attractive starting point for optimization than linear analogs.
Plausibility.55
Novelty.45
Impact.75
Basis · grounding2 papers · 1 computed/note
[1]
paper
Fish beta-defensins (omDB series) are innate-immune effectors that kill bacteria selectively without gross host tissue damage, implying the scaffold has inherent selectivity.
doi: 10.1016/j.molimm.2009.07.018
[2]
sequenceSix cysteines capable of forming three disulfide bonds would rigidify the mature peptide backbone and reduce membrane intercalation entropy compared to linear analogs.
[3]
paper
Toxicity to normal cells is flagged as a critical obstacle for anticancer peptides that disrupt membranes nonspecifically.
doi: 10.2147/idr.s514825
openupdated 2026-06-05

Is there one small region of the peptide that does most of the work of attacking cancer cells?

If a specific short segment is responsible for membrane attack, chemists could swap out just those few building blocks to make a stronger version, without rebuilding the entire molecule. That would accelerate the path from a natural scaffold to an optimized drug candidate.

The hypothesis
The TEMFF segment (residues 41-45 in the full sequence, between the third and fourth cysteines) forms an aromatic-hydrophobic cluster that acts as a membrane-insertion wedge, and truncating or substituting this segment ablates anticancer activity without affecting the disulfide scaffold.
Why it’s plausible
Between the third cysteine (C37) and fourth cysteine (C49) there is a 12-residue loop containing LPTEMFFGPL. This loop is the longest inter-cysteine interval and is enriched in aromatic (F43, F44) and hydrophobic residues, creating a localized hydrophobic patch on what would be the outer face of the beta-defensin fold. Aromatic residues at membrane-water interfaces are known to anchor peptides and facilitate insertion. In beta-defensins this loop region varies most between family members and correlates with potency differences, suggesting it contributes functionally rather than structurally.
Why it matters
Identifying a discrete membrane-insertion element within the scaffold would enable rational engineering of more potent analogs by substituting phenylalanines with tryptophans or by extending the hydrophobic cluster, without redesigning the cysteine framework.
Plausibility.59
Novelty.48
Impact.60
Basis · grounding1 paper · 1 computed/note
[1]
sequenceTEMFFGPL spans the longest inter-cysteine loop (12 residues, C37 to C49); F43 and F44 form a tandem aromatic pair with no equivalent in the flanking loops.
[2]
paper
Hydrophobicity of anticancer peptides plays a crucial role in their mechanism of action against cancer cells, supporting the relevance of localized hydrophobic patches.
doi: 10.1158/1535-7163.mct-10-0811
openupdated 2026-06-05

Could cutting off the unused part and connecting the ends into a ring make this peptide practical to manufacture and use as a drug?

The current molecule is long and expensive to synthesize, and the body breaks down linear peptides quickly. If a shorter, circular version keeps the same cancer-killing activity, it could become manufacturable at realistic cost and survive long enough in the bloodstream to actually reach a tumor.

The hypothesis
Reducing the sequence of pep-05190 to the mature defensin region alone (approximately residues 26-60) and cyclizing it head-to-tail increases both proteolytic stability and anticancer potency compared to the linear precursor construct.
Why it’s plausible
At 60 amino acids pep-05190 exceeds the practical length for cost-effective solid-phase synthesis (the manufacturing axis references cite a 50-residue practical ceiling). The N-terminal signal peptide domain (residues 1-25) has no functional role in a synthetic context and would be cleaved in vivo. Removing it yields a 35-residue mature peptide that is within synthesis limits. Head-to-tail cyclization of short cationic anticancer peptides has been demonstrated to improve potency, and the disulfide staples would further constrain the backbone, resisting protease attack from both ends.
Why it matters
A manufacturable 35-residue cyclized analog retaining the disulfide scaffold would address the two main translational barriers identified in the axis hits: proteolytic instability and high synthesis cost. This is a direct path from a computationally designed precursor to a developable candidate.
Plausibility.57
Novelty.42
Impact.70
Basis · grounding2 papers · 2 computed/notes
[1]
paper
Solid-phase peptide synthesis is limited to approximately 50 amino acids and costs $100-600 per gram; sequences above that length are practically unmanufacturable.
doi: 10.1038/s41467-023-37003-z
[2]
paper
Head-to-tail cyclization of short cationic anticancer peptides improves potency.
doi: 10.1021/acs.jmedchem.5b02025
[3]
sequenceResidues 1-25 constitute a hydrophobic signal peptide that would be cleaved in vivo; the functional cysteine-containing mature region spans only residues 26-60 (35 aa).
[4]
sourceConstrained backbones via cyclization and disulfide bonds improve proteolytic resistance in serum.
openupdated 2026-06-05

Could this peptide find cancer cells on its own by latching onto a molecular marker that most tumors expose on their surface?

Most cancer drugs work only on tumors with a specific mutation or protein. If this peptide homes in on a lipid signal that a broad range of cancers share, it could potentially be useful across many different cancer types without needing to be redesigned for each one.

The hypothesis
The mature form of pep-05190 binds and clusters phosphatidylserine on the outer leaflet of cancer cell membranes, with selectivity determined by the density of exposed phosphatidylserine rather than a proteinaceous receptor.
Why it’s plausible
The mature region carries a net positive charge (R, K, K, H residues) within a cysteine-stapled scaffold that would hold the cationic face rigid. Cancer cells constitutively expose phosphatidylserine on their outer membrane leaflet, while normal cells restrict it to the inner leaflet. Cationic defensin-like peptides have been shown to exploit this asymmetry. The rigid three-disulfide scaffold predicted for a beta-defensin fold would preorganize the charged patch for membrane contact more effectively than a disordered peptide, increasing apparent binding affinity.
Why it matters
If phosphatidylserine exposure is the selectivity determinant rather than a classical protein target, pep-05190 would have activity against a wide range of cancer histotypes that upregulate phosphatidylserine flipping, without requiring a tissue-specific molecular target.
Plausibility.56
Novelty.23
Impact.55
Basis · grounding1 paper · 1 computed/note
[1]
sequenceFour basic residues (R34, K35, K51, H59 in full sequence) cluster in the mature region of a compact 35-residue peptide with 6 cysteines, creating a fixed cationic face.
[2]
paper
Referenced in immunogenicity-safety axis: cationic anticancer peptides with high cancer-cell specificity versus normal cells inhibit tumor growth via membrane interaction.
doi: 10.1074/jbc.m111.279281
details expand to inspect
full evidence table1 metrics
metricvaluetool
ranking score 0.7491890788078308 boltz-2
3-letter notation
Met-Val-Thr-Leu-Val-Leu-Leu-Val-Phe-Leu-Leu-Leu-Asn-Val-Val-Glu-Asp-Glu-Ala-Ala-Ser-Phe-Pro-Phe-Ser-Cys-Pro-Thr-Leu-Ser-Gly-Val-Cys-Arg-Lys-Leu-Cys-Leu-Pro-Thr-Glu-Met-Phe-Phe-Gly-Pro-Leu-Gly-Cys-Gly-Lys-Gly-Phe-Leu-Cys-Cys-Val-Ser-His-Phe
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). Anticancer peptide (pep-05190, v1). PeptideModel. https://peptidemodel.com/card/pep-05190
@peptide{pep05190,
  sequence = {MVTLVLLVFLLLNVVEDEAASFPFSCPTLSGVCRKLCLPTEMFFGPLGCGKGFLCCVSHF},
  target   = {anticancer},
  author   = {peptidemodel},
  year     = {2026},
  status   = {computed}
}
references 3 papers
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