Look up a protein in UniProtKB by accession (e.g. "P04637", "Q9Y6K9", "P0DTC2"). Returns the entry id, reviewed (Swiss-Prot) flag, recommended + alternative protein names, gene names, organism + taxid, sequence length and molecular weight, the curated function description, subcellular locations, Gene Ontology terms (id + term + aspect: biological_process / molecular_function / cellular_component), PDB structure ids, and keywords. Bioinformatics, structural biology, drug-target research, education. Gene-centric sibling: /api/bio/gene. CC-BY UniProt data.
/api/bio/proteinPAYMENT-SIGNATURE.The protein API is a pay-per-call bio endpoint built for AI agents and autonomous software. Look up a protein in UniProtKB by accession (e.g.
There is no signup and no API key. An agent (or any HTTP client) hits the endpoint, receives an x402 "402 Payment Required" challenge, signs a sub-cent USDC payment on Base or Solana, and retries — the data comes back on the paid request. That makes it a drop-in protein data source for an agent tool-use loop, an MCP host, or a backend that needs bio data on demand without onboarding to yet another vendor portal.
| Name | Type | Description |
|---|---|---|
accessionrequired | string | min 2 chars · max 20 chars · match ^[A-Za-z0-9]+$ |
# 1. Probe with no auth → 402 envelope with PaymentRequirements curl -sS 'https://2s.io/api/bio/protein?accession=xx' # 2. Sign + retry with PAYMENT-SIGNATURE: curl -sS 'https://2s.io/api/bio/protein?accession=xx' \ -H 'PAYMENT-SIGNATURE: <base64-json-payload>' # Or use the canonical runner (handles probe → sign → retry): # EVM_PRIVATE_KEY=0x... node --env-file=.env.local \ # --experimental-strip-types scripts/x402-pay.ts \ # 'https://2s.io/api/bio/protein?accession=xx'
import { TwoS } from '@2sio/sdk'
const client = new TwoS({
privateKey: process.env.EVM_PRIVATE_KEY as `0x${string}`,
})
const result = await client.bio.protein({
"accession": "xx"
})
console.log('endpoint:', result.endpoint)
console.log('cost:', result.costUsd, 'USDC')
console.log('tx:', result.settlement?.txHash)
console.log('data:', result.data)import os
from twosio import TwoS
client = TwoS(private_key=os.environ["EVM_PRIVATE_KEY"])
result = client.bio.protein(accession="xx")
print("endpoint:", result.endpoint)
print("cost:", result.cost_usd, "USDC")
print("tx:", (result.settlement or {}).get("tx_hash"))
print("data:", result.data)// 1. Add @2sio/mcp to your MCP host config (Claude Desktop example below).
// EVM_PRIVATE_KEY funds x402 payments per call.
// claude_desktop_config.json
{
"mcpServers": {
"2sio": {
"command": "npx",
"args": ["-y", "@2sio/mcp"],
"env": { "EVM_PRIVATE_KEY": "0x..." }
}
}
}
// 2. Once the server is running, agents call this tool via standard MCP:
{
"jsonrpc": "2.0",
"id": 1,
"method": "tools/call",
"params": {
"name": "bio.protein",
"arguments": {
"accession": "xx"
}
}
}| Field | Type | Description |
|---|---|---|
ok | boolean | one of: true |
items | array | |
total | integer | Total matching rows upstream; null when unknown. |
source | object |
{
"ok": true,
"items": [
{
"protein": {
"accession": "example",
"entryId": "example",
"reviewed": false,
"proteinName": "example",
"alternativeNames": [
"example"
],
"genes": [
"example"
],
"organism": {
"scientificName": "example",
"commonName": "example",
"taxid": 1
},
"lengthAa": 1,
"molecularWeightDa": 1,
"function": "example",
"subcellularLocations": [
"example"
],
"goTerms": [
{
"id": "example",
"term": "example",
"aspect": "example"
}
],
"pdbStructures": [
"example"
],
"keywords": [
"example"
],
"uniprotUrl": "example"
}
}
],
"total": 1,
"source": {
"provider": "example",
"url": "example",
"license": "example"
}
}