Tissue-repair signaling fragment (RGDS)
A tiny piece of the protein fibronectin that cells grab onto to stick and spread; the original discovery that launched RGD-based drug design, 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
RGDS is a four-amino-acid fragment (Arg-Gly-Asp-Ser) cut out of the protein fibronectin — the part of the protein that cells actually grab onto. It was the first short peptide ever shown to substitute for a much larger cell-adhesion protein, and that finding launched an entire branch of biology built around the three-letter "RGD" motif. It is not a drug; it is a research tool and the structural template that later RGD-based drug candidates were built from.
History
RGDS was identified in 1984 by Pierschbacher and Ruoslahti at the Burnham Institute, who showed that small synthetic fragments of fibronectin could reproduce the cell-attachment activity of the intact protein (Pierschbacher 1984, Nature). The paper isolated the active site to the tripeptide RGD with serine extending it to a tetrapeptide; that simple sequence turned out to be the recognition motif used by an entire family of cell-surface receptors — the integrins — and the same RGD signature later turned up in unrelated proteins ranging from snake-venom disintegrins (Okuda 2001) to viral attachment proteins. The discovery is one of the foundational results that made it possible to design peptide-based integrin inhibitors as a drug class, most prominently the cyclic RGD pentapeptide Cilengitide developed in the early 1990s (Mas-Moruno 2010).
What it does
RGDS binds to integrins — the receptors cells use to attach to the extracellular matrix — and competes with the natural ligand for that binding site. When added to a culture of cells sitting on a fibronectin-coated surface, free RGDS in solution can occupy the integrin pocket and prevent the cell from adhering. The same mechanism makes RGD-containing peptides useful as starting points for blocking integrins involved in angiogenesis, tumor cell adhesion, and platelet aggregation. The linear RGDS form is considerably weaker and less selective than constrained cyclic RGD analogs — the cyclic pentapeptide c(RGDfV) showed 100- to 1000-fold higher activity against αvβ3 than linear reference peptides (Mas-Moruno 2010), and that selectivity gain is the reason essentially all clinical-grade RGD drug candidates are cyclic rather than linear.
Mechanism
The integrins recognized by RGD-containing ligands include αvβ3, αvβ5, and α5β1 (Mas-Moruno 2010); these receptors mediate cell adhesion, migration, and angiogenic signaling. RGDS engages the integrin headpiece at the same binding cleft used by fibronectin's larger tenth type-III repeat, mimicking the small surface loop that fibronectin presents to the receptor. Because the linear tetrapeptide lacks the conformational constraint that cyclization imposes, it samples many backbone conformations in solution and pays an entropic cost on binding — which is why the linear form is used mainly as a reference compound, with cyclized and N-methylated derivatives doing the heavy lifting in drug-development programs. RGD-binding integrins also have non-RGD-recognizing binding modes: tumstatin, for example, contains two αvβ3-binding sites that operate independently of the RGD motif (Maeshima 2000), which is part of why RGD-blocking alone is not a complete strategy for inhibiting these receptors.
Evidence
- Human: No human trials of linear RGDS itself. RGD-derived analogs have reached the clinic — cilengitide, a cyclic RGD pentapeptide, advanced through Phase II and Phase III trials in glioblastoma and several other tumor types (Mas-Moruno 2010). The non-RGD integrin-binding peptide ATN-161 has also been evaluated, including as a candidate for SARS-CoV-2 entry inhibition (Beddingfield 2021).
- In vitro: Linear RGDS reproduces the cell-attachment activity of intact fibronectin in cell-adhesion assays (Pierschbacher 1984). RGD-containing motifs from disintegrins isolated from Echis snake venoms also mediate integrin-dependent platelet inhibition (Okuda 2001).
Known effects
- Integrin blockade (αvβ3, αvβ5, α5β1) — Mechanistic; reference compound for RGD-binding integrins (Mas-Moruno 2010).
- Cell-adhesion competition — Established in vitro on fibronectin-coated substrates (Pierschbacher 1984).
- Template for anti-angiogenic drug design — Cyclic RGD analogs (e.g. cilengitide) reached clinical evaluation in oncology (Mas-Moruno 2010).
- Template for grafted-peptide cancer therapeutics — Stable peptide scaffolds incorporating RGD-type recognition continue to be explored as antibody alternatives (Chowdhury 2025).
Regulatory status
RGDS itself is a research-grade peptide, not an approved drug, and has no FDA or EMA approval. Among RGD-derived clinical candidates, cilengitide reached Phase III for glioblastoma but did not gain marketing authorization (Mas-Moruno 2010). No WADA listing applies to RGDS as a non-therapeutic research reagent.
Related peptides
The RGD family is large; this card sits at the root of it. Related entries on the platform should describe constrained cyclic RGD analogs, RGD-bearing disintegrins, and non-RGD integrin-binding peptides such as ATN-161 (Beddingfield 2021). Tumstatin-derived fragments offer a contrast case — they bind αvβ3 through RGD-independent epitopes (Maeshima 2000).
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.
Is this peptide actually preventing cells from repairing tissue instead of helping them?
If correct, this would flip how RGDS is used in research and drug development: instead of testing it as a wound-healing aid, scientists would focus on applications where blocking cell adhesion is the goal, such as preventing unwanted clotting or stopping tumor blood vessel growth. Anyone funding wound-care products built around RGDS would want to know this first.
Does the fourth building block in this short peptide make it prefer one docking receptor over another, and does that difference matter for patients?
If the serine shifts the peptide toward the receptor associated with wound and bone repair, it could help engineers design simpler, cheaper peptide drugs for healing without accidentally triggering unwanted blood-vessel overgrowth as a side effect. This would be useful for people recovering from bone injuries or chronic wounds.
Could wrapping this fragile four-amino-acid peptide inside a tough protein frame make it survive in the bloodstream for hours instead of minutes?
Short peptides are typically digested within minutes after injection, which has blocked RGDS from becoming a real medicine. If this scaffolding approach could extend its life to four or more hours in the body, it might open a new class of anti-cancer or anti-thrombotic drugs that are simpler and potentially cheaper than current antibody therapies. Researchers and biotech investors looking for novel intellectual property in this space would be the first to benefit.
Does this peptide deliver only a partial signal inside the cell, and could that incomplete signal be deliberately useful?
Full adhesion blockade can disrupt normal tissue function, but a peptide that merely dampens the signal without shutting it off might control chronic inflammation or scar-tissue buildup with fewer side effects. If this partial-agonist behavior holds up, it could guide the design of gentler therapies for conditions like pulmonary fibrosis or certain autoimmune diseases where the immune response needs to be dialed down, not eliminated.
Could a single simple chemical modification to this peptide match the performance of expensive ring-shaped drug candidates at a fraction of the cost?
Cyclic RGD peptides such as cilengitide have shown promise in blocking tumor blood-vessel growth but are expensive and complex to make. If replacing just one amino acid building block with a slightly modified version achieves comparable potency and stability, it could lower the manufacturing barrier significantly, making RGD-based treatments more accessible and possibly opening the door to oral formulations that patients could take as a pill.
Could this simple, easy-to-make peptide compete with the virus for a cell-surface receptor and reduce how much virus gets in?
If the SARS-CoV-2 spike protein genuinely uses an RGD-like grip on human cell-surface receptors as part of entry, then flooding those sites with the peptide RGDS could partially block that route. Because RGDS is chemically straightforward and inexpensive to produce, even a modest effect could be worth exploring as a nasal-spray format for people at high risk of severe infection. This hypothesis also tests a broader scientific question: whether the RGD sequence in the spike protein is a real functional handle or just a coincidence.
▸full evidence table1 metrics
| metric | value | tool |
|---|---|---|
| ranking score | 0.6219319701194763 | boltz-2 |
▸3-letter notation
▸recipeboltz-2 2.2.1
| parameter | value |
|---|---|
| model | boltz-2 2.2.1 |
| weights | — |
| hardware | vast_v100_32gb |
| mlx version | — |
| python | — |
| random seed | 1 |
| msa strategy | none_monomer |
| runtime | — |
| predicted by | — |
| predicted at | 2026-05-23 |
▸citationbibtex
@peptide{pep10784,
sequence = {RGDS},
target = {tissue-repair},
author = {peptidemodel},
year = {2026},
status = {computed}
}