pe
pep-10791 v1 CC-BY-SA-4.0

Muscle-growth booster peptide: follistatin fragment (1-27)

A naturally occurring fragment of follistatin that blocks myostatin and related signals, freeing muscles to grow; used only as a lab research tool.

statusbioassayed targetACTIVIN-A length28 aa refs1
endogenous-fragmentfollistatin-deriveddisulfideactriib-antagonist
EARLY ENTRY This candidate is newly indexed — supporting evidence is still being added. Have a paper or data point? Contribute below.
status 5 / 5
prediction metrics boltz-2 2.2.1
ipTM0.226
pTM0.685
avg pLDDT72.3
ranking score0.624
STRUCTURE · PEP-10791 × ACTIVIN-A
ranking0.624
target interface 4.5Å peptide drag rotate · ctrl+scroll zoom · right-click pan
boltz-2 2.2.1 · mmCIF ↓ download
sequence28 aa
151015202528
GNDLCYEPCECFED LECNPESTQYEDEC
in the news 3 articles
Hypotheses1 direction▾ 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

Does this 28-amino-acid piece actually bind the proteins it is supposed to block?

If the fragment cannot block its targets, researchers could redirect effort toward redesigning it as a scaffold instead of using the native piece.

The hypothesis
The low ipTM (0.226) for pep-10791 binding to its annotated targets (activin-A, ActRIIB, GDF-8, GDF-11) indicates the 28-aa fragment does not recapitulate the multi-domain follistatin binding interface and therefore binds none of the four annotated targets with meaningful affinity as a monomeric peptide.
Why it’s plausible
Full follistatin neutralizes activins/GDFs through a three-domain clamp (NtD, FSD1, FSD2). The 28-aa fragment covers only a sliver of the NtD disulfide scaffold. An ipTM of 0.226 is well below the 0.5 threshold for credible modelled interfaces, suggesting the cysteine-rich core alone lacks the extended surface needed to occlude the ActRIIB binding epitope on activin-A or GDF-8.
Why it matters
If the fragment cannot bind annotated targets, the entire actriib-antagonist annotation is unvalidated, and any muscle-growth or fibrosis-modulation claims built on that annotation are unfounded. Conversely, confirming lack of binding focuses development toward engineered scaffolds rather than the native fragment.
Plausibility.72
Novelty.55
Impact.80
Basis · grounding2 computed/notes
[1]
structureBoltz-2 complex ipTM=0.2262, pLDDT=72.3, well below the reliable binding threshold of ~0.5
[2]
sequence28-aa fragment GNDLCYEPCECFEDLECNPESTQYEDEC contains 8 cysteines but is too short to recapitulate the tri-domain follistatin clamp needed for activin-A occlusion
details expand to inspect
full evidence table2 metrics
metricvaluetool
ipTM 0.2262854129076004 boltz-2
ranking score 0.6240484118461609 boltz-2
3-letter notation
Gly-Asn-Asp-Leu-Cys-Tyr-Glu-Pro-Cys-Glu-Cys-Phe-Glu-Asp-Leu-Glu-Cys-Asn-Pro-Glu-Ser-Thr-Gln-Tyr-Glu-Asp-Glu-Cys
recipeboltz-2 2.2.1
parametervalue
modelboltz-2 2.2.1
weights
hardwarevast_v100_32gb
mlx version
python
random seed1
msa strategycolabfold_local
runtime
predicted by
predicted at2026-05-22
citationbibtex
peptidemodel (2026). Muscle-growth booster peptide: follistatin fragment (1-27) (pep-10791, v1). PeptideModel. https://peptidemodel.com/card/pep-10791
@peptide{pep10791,
  sequence = {GNDLCYEPCECFEDLECNPESTQYEDEC},
  target   = {activin-a},
  author   = {peptidemodel},
  year     = {2026},
  status   = {bioassayed}
}
clinical trials 0 trials · checked 2026-05-22
0
no registered clinical trials as of 2026-05-22; we'll re-check periodically
references 1 papers
discussion no comments
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