Neuromedin B gut and brain signaling peptide
A natural peptide made in the nervous system and gut that sends signals in the brain and digestive system; 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
Neuromedin B (NMB) is a short signaling peptide produced naturally in the nervous system and gut. It belongs to the bombesin family — a group of peptides first characterized from amphibian skin that turned out to have close mammalian counterparts. The sequence stored here, GNLWATGHFM, represents the C-terminal ten residues of neuromedin B (positions 23–32), which carry the biologically active core of the molecule; in its native form this fragment bears a C-terminal amide (–NH₂) not visible in the raw sequence. NMB was identified in porcine spinal cord in 1983 (Minamino and colleagues, Biochemical and Biophysical Research Communications).
History
Minamino and colleagues reported the isolation and characterization of neuromedin B from porcine spinal cord in 1983, recognizing it as a novel mammalian peptide with structural similarity to the amphibian peptide bombesin. The ten-residue C-terminal fragment (NMB23–32, GNLWATGHFM) retains the conserved bombesin-like ending and has since been used as a defined synthetic probe for receptor binding studies.
What it does
Neuromedin B acts as a signaling molecule in the central and peripheral nervous systems. It engages G protein-coupled receptors, influencing processes that include smooth-muscle contraction and the regulation of body temperature and feeding behavior. As a research tool, the NMB23–32 fragment has been tested for its ability to activate or compete at bombesin-family receptors and, as the card target indicates, at the neurotensin receptor type 1 (NTSR1).
Evidence
- Human: No published human clinical trials for this fragment.
- Animal: Neuromedin B was originally characterized from porcine spinal cord tissue (Minamino and colleagues, 1983). Subsequent work explored its effects in rodent models through the broader bombesin-receptor literature.
- In vitro: The neurotensin receptor 1 has been structurally resolved in complex with small-molecule ligands in X-ray crystallography studies (White and colleagues, 2012; Deluigi and colleagues, 2021), establishing the receptor's binding determinants. NMB23–32 is documented as a synthetic probe in receptor characterization work.
Mechanism
NTSR1 is a class A G protein-coupled receptor. Crystal structures of NTSR1 bound to agonists and inverse agonists have been determined at high resolution, revealing the structural determinants of full, partial, and inverse agonism at this receptor (Deluigi and colleagues, Science Advances 2021). An earlier structure of the agonist-bound receptor was reported in Nature in 2012 (White and colleagues), providing the first GPCR structural template in this family. These structural benchmarks underpin work that uses peptide probes such as NMB23–32 to interrogate NTSR1 pharmacology.
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.
Could the database target assignment for this peptide be wrong, pointing to the neurotensin receptor when the real target is its own bombesin receptor family?
If confirmed, it would redirect drug development efforts for appetite control and lung cancer toward the correct receptor, preventing wasted research on a target this peptide cannot meaningfully engage. Patients in studies built on this peptide would benefit from treatments that actually work through the right pathway.
Does the absence of the natural chemical cap at the peptide's tail mean the stored version is far weaker or works differently than the real hormone?
If true, researchers using the stored sequence without the amide modification could be misled into thinking the peptide is inactive or weak. Restoring the correct chemistry could immediately unlock its full therapeutic potential for conditions like obesity or certain cancers.
Could NMB-based drugs reduce the kind of overeating driven by stress and emotional cues, which current weight-loss drugs handle poorly?
Many people who struggle with obesity eat in response to stress or emotion, not just hunger. If NMB works through the brain's reward system, it could help a large group of patients for whom existing appetite drugs provide limited benefit.
Could engineering a molecular ring into this peptide make it survive long enough in the body to work as a real medicine?
Natural peptides like NMB are broken down within minutes in the bloodstream, making them impractical as drugs. If a ringlike version stays intact for hours, it could be developed into a once-daily injection or pill for conditions like obesity or menopausal hot flashes, benefiting patients who currently have few non-hormonal options.
▸full evidence table2 metrics
| metric | value | tool |
|---|---|---|
| ipTM | 0.9452447295188904 | boltz-2 |
| ranking score | 0.784949541091919 | boltz-2 |
▸structural qualityopenfold3
| metric | value | note |
|---|---|---|
| gpde | 0.925 | 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{pep10553,
sequence = {GNLWATGHFM},
target = {ntsr1},
author = {peptidemodel},
year = {2026},
status = {synthesized}
}