Painkiller-pathway research peptide (Pro3-Dynorphin A 1-11 amide)
A lab-made version of the body's natural opioid signal dynorphin, engineered to selectively activate the brain's main pain-relief receptor; used only as a lab research tool.
A researcher, an agent, or an algorithm wrote down the sequence and picked a target to hit.
An AI model like OpenFold3 or AlphaFold built a 3D structure and scored how well it fits the binding site.
A second contributor repeated the computation on their own hardware and the scores matched.
A chemistry service or a researcher ordered the sequence, it was manufactured, and mass spectrometry confirmed the right molecule was produced.
A binding or activity measurement confirmed that it actually does what the computer predicted — or didn't.
What this is
(Pro3)-Dynorphin A (1-11) amide is a synthetic, 11-residue analog of dynorphin A, one of the body's natural opioid signaling peptides. The parent dynorphin A peptides are endogenous ligands that act at opioid receptors — proteins embedded in nerve cells that regulate pain perception, mood, and stress responses. This analog carries a proline substitution at position 3 of the sequence and a C-terminal amide modification; the amide cap is not encoded in the raw sequence shown but protects the peptide's C-terminus from enzymatic degradation. It is a research tool used to study the pharmacology of the mu-opioid receptor (OPRM1), a class A G protein-coupled receptor and the principal target of both endogenous opioid peptides and opioid analgesic drugs.
What it does
Dynorphin A and its shortened fragments bind to opioid receptors in the central and peripheral nervous system to modulate pain, reward signaling, and stress. The mu-opioid receptor (OPRM1), which this analog targets, is the receptor responsible for the analgesic and reinforcing effects of opioid drugs. Within reward-relevant brain regions such as the ventral tegmental area and nucleus accumbens, mu-opioid receptor activation facilitates dopamine transmission and shapes motivation and affect (Allichon and colleagues, 2026). The broader opioid receptor family — mu, delta, kappa, and nociceptin — evolved from a common ancestor and share considerable structural homology while mediating distinct behavioral outcomes (Huang and colleagues, 2022; Pasternak and colleagues, 2013).
Evidence
- Human: No human trials on (Pro3)-Dynorphin A (1-11) amide are published or registered on ClinicalTrials.gov. This compound is a pharmacological research tool, not a clinical drug.
- Animal: No animal in vivo data for this specific analog are available in the current dossier.
- In vitro: No binding affinity or functional assay data (Ki, EC50, or selectivity ratios) for this specific analog are available in the current dossier.
Mechanism
The mu-opioid receptor (OPRM1) is a class A G protein-coupled receptor (GPCR). Opioid receptor pharmacology has been studied for decades; Pasternak and colleagues (2013) provide a comprehensive account of how the mu-opioid receptor concept evolved from early radioligand binding studies to molecular cloning and splice-variant characterization. The delta opioid receptor — the first opioid receptor to be cloned by molecular methods — was identified in 1992 by Evans and colleagues using functional expression in COS cells, demonstrating homology to other GPCRs including somatostatin and angiotensin receptors; the mu receptor's cloning shortly followed, establishing the molecular basis of opioid pharmacology.
Dynorphin-derived peptides and their analogs are studied in this context as structural probes: modifications such as residue substitutions at position 3 or C-terminal amidation alter receptor binding profiles and proteolytic stability, enabling researchers to dissect the contributions of individual receptor subtypes to pain and reward circuits. The specific binding properties of (Pro3)-Dynorphin A (1-11) amide require direct experimental data not yet available in this dossier.
Open questions
- Binding affinity (Ki) and selectivity ratios at mu, delta, and kappa opioid receptors for this specific analog remain to be confirmed from primary literature.
- Whether the Pro3 substitution alters receptor subtype selectivity relative to the parent dynorphin A (1-11) amide has not been documented in the current source set.
- Proteolytic stability of this analog compared with the parent sequence is not characterized in available sources.
- Functional bias (G protein vs. β-arrestin signaling at OPRM1) has not been reported for this compound.
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.
If the chemical group protecting the end of this dynorphin fragment from being broken down is replaced with one that enzymes cannot destroy, would the resulting peptide last long enough in the body to be useful as a painkiller?
If true, this engineering step could convert a short-lived research tool into a drug candidate for pain management, potentially providing a new category of opioid analgesic with a defined receptor selectivity profile and longer duration of action.
Could the distinctive charged cluster in this dynorphin analog cause the mu-opioid receptor to activate pain-relief pathways while sending weaker signals through the addiction pathway, compared to standard opioid drugs?
If true, this could lead to a new class of painkiller that separates the therapeutic benefit of opioid pain relief from its addictive effects, a breakthrough that could help millions of chronic pain patients without fueling the opioid addiction crisis.
Does the electrically charged tail of this dynorphin fragment first land on the outside of the opioid receptor through electrical attraction, before the front end slots into the active site, making it bind differently from simpler opioid peptides?
If true, this binding mechanism could produce a drug that stays attached to the receptor for a different length of time than current opioids, potentially offering better pain relief with less risk of tolerance or addiction through a genuinely different interaction profile.
Does replacing one flexible amino acid with a rigid proline in dynorphin A change which opioid receptor it mainly activates, potentially making a version that relieves pain without causing the unpleasant feelings associated with kappa-opioid drugs?
If true, this structural insight could guide the design of new dynorphin-based pain drugs that work through the pain-relieving receptor rather than the one that causes sedation and dysphoria, contributing to safer opioid alternatives.
▸full evidence table2 metrics
| metric | value | tool |
|---|---|---|
| ipTM | 0.8614767789840698 | boltz-2 |
| ranking score | 0.8106325268745422 | boltz-2 |
▸structural qualityopenfold3
| metric | value | note |
|---|---|---|
| gpde | 0.993 | global PDE — lower = better |
| disorder | NaN | fraction disordered |
▸3-letter notation
▸recipeboltz-2 1.0
| parameter | value |
|---|---|
| model | boltz-2 1.0 |
| weights | — |
| hardware | nvidia_nim_api |
| mlx version | — |
| python | — |
| random seed | — |
| msa strategy | none |
| diffusion samples | 1 |
| runtime | — |
| predicted by | mlx@peptide |
| predicted at | 2026-04-24 |
▸citationbibtex
@peptide{pep10706,
sequence = {YGPFLRRIRPK},
target = {oprm1},
author = {peptidemodel},
year = {2026},
status = {computed}
}