Biotin-tagged CGRP nerve-signal tracer (canine/mouse/rat)
A lab-only version of a natural nerve-signaling protein, tagged with biotin so researchers can track exactly where it binds in the body; 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
Biotin-α-CGRP is a laboratory version of α-CGRP (alpha calcitonin gene-related peptide) carrying a biotin tag, used as a research tool rather than a therapeutic. α-CGRP itself is a 37-amino-acid neuropeptide produced by sensory neurons that signals through receptors in the calcitonin/CGRP family (Hay 2018). The sequence stored here (SCNTATCVTHRLAGLLSRSGGVVKDNFVPTNVGSEAF) corresponds to the rat α-CGRP backbone — also conserved in canine and mouse — and the biotin tag is appended separately as a detection handle, not represented in the raw 37-letter sequence. The tag lets researchers pull the peptide down with streptavidin and trace where it binds, which is why this reagent shows up in studies dissecting the calcitonin receptor and amylin-receptor pharmacology that underlies weight-loss and migraine drug development.
What it does
In the body, native α-CGRP acts on a small family of class B (secretin-like) G-protein-coupled receptors built from two scaffolds — the calcitonin receptor (CTR) and the calcitonin-receptor-like receptor (CLR) — each of which pairs with one of three receptor activity-modifying proteins (RAMPs) to define ligand selectivity (Hay 2018, Barwell 2012). CLR with RAMP1 forms the canonical CGRP receptor, while CTR paired with RAMPs forms the amylin receptors (AMY₁, AMY₂, AMY₃) that respond to both amylin and CGRP (Hay 2018). Biotin-α-CGRP itself is not used to "do" anything in vivo — it is used in binding assays where the biotin tag allows the peptide to be captured, visualized, or affinity-purified so that receptor interactions can be characterized (Lee 2016).
Mechanism
α-CGRP and the closely related β-CGRP differ by only a few residues and are produced by alternative splicing of the calcitonin gene, with α-CGRP predominating in primary sensory neurons and β-CGRP more prominent in enteric autonomic neurons (Mulderry 1988). The peptide family as a whole — calcitonin, α-CGRP, β-CGRP, amylin, adrenomedullin and adrenomedullin 2/intermedin — binds CTR or CLR, with the RAMP partner shifting the receptor's preference between ligands (Hay 2018). Mechanistic work on calcitonin and amylin receptors has shown that peptide engagement involves a two-domain interaction: the C-terminus of the peptide first docks to the receptor extracellular domain, and the N-terminus then engages the transmembrane bundle to trigger activation (Lee 2016, Barwell 2012). Because Biotin-α-CGRP carries the α-CGRP backbone intact, it engages this same family of receptors and is used to probe them; the biotin moiety is a handle for downstream detection, not a pharmacophore.
Evidence
- Human: No human clinical use. This reagent is a research tool; no registered clinical trials.
- Animal: Underlying α-CGRP biology has been mapped in rat sensory and autonomic neurons, where differential α/β-CGRP expression was first defined (Mulderry 1988).
- In vitro: Used in biochemical characterizations of calcitonin- and amylin-receptor binding mechanisms (Lee 2016); the broader pharmacology of the calcitonin/CGRP receptor family — including CTR/CLR identity, RAMP heterodimer composition, and ligand cross-reactivity — is summarized in IUPHAR Review 25 (Hay 2018) and earlier in Barwell 2012.
Regulatory status
Biotin-α-CGRP is a research reagent, not a drug. It has no FDA, EMA, or WADA classification. The native α-CGRP / CGRP-receptor axis is the target of approved migraine therapeutics (the gepants and CGRP-pathway monoclonal antibodies), and the broader calcitonin/CGRP/amylin receptor family is therapeutically relevant to osteoporosis, diabetes, obesity, lymphatic insufficiency, migraine and cardiovascular disease (Barwell 2012, Hay 2018) — but those drug classes are distinct molecules, not this peptide.
Open questions
- The relative affinity of α-CGRP vs β-CGRP at each CTR/RAMP and CLR/RAMP combination is still incompletely mapped (Hay 2018).
- For Biotin-α-CGRP specifically, the position and linker chemistry of the biotin tag are not documented in this card's references — users of the reagent should consult the supplier's characterization before assuming the tag is inert with respect to receptor binding.
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.
Does the single amino acid difference between rat and human alpha-CGRP mean the rat peptide activates different receptor sub-types more strongly than the human version?
If true, decades of CGRP research done in rats may not translate directly to humans, which would be an important recalibration for the entire migraine drug development field and could explain why some CGRP-targeting drugs showed unexpected profiles when moving from animal studies to clinical trials.
Could attaching biotin at two different locations on alpha-CGRP produce two distinct probes, each labelling a different CGRP receptor sub-type in tissue?
If achievable, researchers could finally map the exact locations of CGRP receptor sub-types throughout the body in a single experiment, accelerating the design of drugs that hit only the desired receptor for migraine treatment or bone protection.
▸full evidence table2 metrics
| metric | value | tool |
|---|---|---|
| ipTM | 0.7213250994682312 | openfold3-mlx |
| ranking score | 0.8252753019332886 | openfold3-mlx |
▸structural qualityopenfold3
| metric | value | note |
|---|---|---|
| gpde | 0.914 | global PDE — lower = better |
| disorder | 0.215 | fraction disordered |
| chain pair ipTM (A, B) | 0.721 | interface quality |
▸3-letter notation
▸recipeopenfold3-mlx 0.3.1
| parameter | value |
|---|---|
| model | openfold3-mlx 0.3.1 |
| weights | aedd8f3eb814e392… |
| hardware | apple_m4_base_16gb |
| mlx version | 0.31.1 |
| python | 3.14.3 |
| random seed | 42 |
| msa strategy | colabfold |
| diffusion samples | 1 |
| runtime | 461s |
| predicted by | mlx@peptide |
| predicted at | 2026-04-24 |
python3 openfold3/run_openfold.py predict --query_json {query.json} --runner_yaml examples/example_runner_yamls/mlx_runner.yml --output_dir {output_dir} --num_diffusion_samples 1 ▸citationbibtex
@peptide{pep10643,
sequence = {SCNTATCVTHRLAGLLSRSGGVVKDNFVPTNVGSEAF},
target = {calcr},
author = {peptidemodel},
year = {2026},
status = {synthesized}
}