> ## Documentation Index
> Fetch the complete documentation index at: https://docs.oneshotagent.com/llms.txt
> Use this file to discover all available pages before exploring further.
# Protein Sequence
> Get the reference amino-acid sequence of a protein or an isoform by UniProt accession, with its length, weight, checksums and isoforms.
Protein sequences from UniProt under CC BY 4.0, attributed to the UniProt Consortium. Medical or genetic information is for research and education only. The sequence is the reference sequence UniProtKB holds for a protein, never an individual’s sequence. Covers reviewed and unreviewed entries; an accession with an isoform suffix (P04637-2) returns that isoform’s sequence. Returns the one-letter sequence, length, molecular weight in daltons, CRC64 and MD5 checksums, gene, organism and the isoforms the entry lists. sequence\_version and last\_sequence\_update describe the entry, also for an isoform. UniProt releases updates every eight weeks. Absent values are null. A merged, demerged or deleted accession returns no protein and the source’s inactive reason with any replacement accessions. No match, including an isoform the entry does not list, returns null for both.
## Authentication
Requires x402 payment in the `payment-signature` header.
## Request Body
The UniProt accession, for example P04637, or an isoform accession, for example P04637-2.
## Response (200 OK)
Top-level envelope: `success` (boolean) and `data` (object). All fields below are nested under `data`.
Durable job ID for audit and lookup
Job status: `completed`
Always `protein_sequence`
The answer, described under Result below
Where the answer came from and when
The public body the data comes from. Always `UniProt Consortium`.
`public` when the data comes from a public body, `commercial` otherwise
When the lookup was made, as an ISO 8601 UTC time
When the source says the fact was last updated, or `null` when the source gives no date
## Result
Nested under `data.result`.
Protein. `null` when the source gives no value.
Accession. `null` when the source gives no value.
Entry name. `null` when the source gives no value.
Reviewed.
Is isoform.
Gene. `null` when the source gives no value.
Organism.
Scientific name. `null` when the source gives no value.
Taxon id. `null` when the source gives no value.
One-letter amino-acid sequence. `null` when the source gives no value.
Length. `null` when the source gives no value.
Molecular weight da. `null` when the source gives no value.
Crc64. `null` when the source gives no value.
Md5. `null` when the source gives no value.
The entry’s sequence version. `null` when the source gives no value.
The date the entry’s sequence last changed, YYYY-MM-DD. `null` when the source gives no value.
Isoforms.
Accession. `null` when the source gives no value.
Name. `null` when the source gives no value.
Synonyms.
Isoform sequence status, lower-cased: displayed, described or another source value. `null` when the source gives no value.
Inactive. `null` when the source gives no value.
The source’s reason for inactivation, lower-cased: merged, demerged or deleted. `null` when the source gives no value.
Replaced by.
```bash cURL theme={null}
curl -X POST https://win.oneshotagent.com/v1/tools/lookup/protein-sequence \
-H "Content-Type: application/json" \
-H "payment-signature: " \
-d '{
"accession": "P00001"
}'
```
```javascript JavaScript theme={null}
const response = await fetch("https://win.oneshotagent.com/v1/tools/lookup/protein-sequence", {
method: "POST",
headers: {
"Content-Type": "application/json",
"payment-signature": paymentProof,
},
body: JSON.stringify({
"accession": "P00001"
}),
});
```
```typescript SDK theme={null}
const result = await agent.tool('lookup/protein-sequence', {
accession: 'P00001'
});
console.log(result.data.result);
console.log(result.data.evidence);
```
```json Response (200) theme={null}
{
"success": true,
"data": {
"request_id": "uuid",
"receipt_id": "rcpt_...",
"status": "completed",
"tool": "protein_sequence",
"result": {
"protein": null,
"inactive": {
"reason": "demerged",
"replaced_by": [
"P99999",
"P99998"
]
}
},
"evidence": {
"source": "UniProt Consortium",
"source_kind": "public",
"retrieved_at": "2026-01-15T12:00:00.000Z",
"calls": [
{
"retrieved_at": "2026-01-15T12:00:00.000Z"
}
],
"as_of": null
}
}
}
```
See [Pricing](/pricing) for this tool's price. A wallet (x402) call receives it in the 402 quote before anything is charged; a call paid from prepaid credits is charged when the API accepts the request and answers `200`.
## Notes
* Results return inline. The finished job stays available at `/v1/requests/{request_id}`
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