diff --git a/main.nf b/main.nf
index 53b88a8..3f60b17 100644
--- a/main.nf
+++ b/main.nf
@@ -56,40 +56,74 @@ process POCKETMINER {
             fi
         fi
 
-        # Method 3: Download from MinIO via wget
+        # Method 3: Download from MinIO using python boto3/S3
         if [ -z "\$PDB_FILE" ]; then
-            S3_PATH="\$(echo '${pdb_path}' | sed 's|^s3://||')"
-            MINIO_URL="http://datalake-hl.datalake.svc.cluster.local:9000/\$S3_PATH"
-            echo "Downloading from MinIO: \$MINIO_URL" >> run.log
-            wget -q "\$MINIO_URL" -O input.pdb 2>> run.log || true
-            if [ -f input.pdb ] && [ -s input.pdb ]; then
-                echo "Downloaded from MinIO (\$(wc -c < input.pdb) bytes)" >> run.log
-                PDB_FILE="input.pdb"
-            else
-                echo "wget download failed, trying python..." >> run.log
-                rm -f input.pdb
-            fi
-        fi
-
-        # Method 4: Download from MinIO using python urllib
-        if [ -z "\$PDB_FILE" ]; then
-            S3_PATH="\$(echo '${pdb_path}' | sed 's|^s3://||')"
+            S3_PATH="${pdb_path}"
             ENDPOINT="\${AWS_ENDPOINT_URL:-http://datalake-hl.datalake.svc.cluster.local:9000}"
-            echo "Downloading with python from: \$ENDPOINT/\$S3_PATH" >> run.log
+            echo "Downloading via python S3 client from: \$ENDPOINT" >> run.log
+            echo "S3 path: \$S3_PATH" >> run.log
+            echo "AWS_ACCESS_KEY_ID: \${AWS_ACCESS_KEY_ID:+set}" >> run.log
+            echo "AWS_SECRET_ACCESS_KEY: \${AWS_SECRET_ACCESS_KEY:+set}" >> run.log
+            echo "AWS_ENDPOINT_URL: \${AWS_ENDPOINT_URL:-not set}" >> run.log
             python -c "
-import urllib.request
-url = '\$ENDPOINT/\$S3_PATH'
+import os, sys
+s3_path = '\$S3_PATH'
+endpoint = '\$ENDPOINT'
+
+# Parse s3://bucket/key
+path = s3_path.replace('s3://', '')
+parts = path.split('/', 1)
+bucket = parts[0]
+key = parts[1] if len(parts) > 1 else ''
+
+print(f'Bucket: {bucket}, Key: {key}')
+print(f'Endpoint: {endpoint}')
+
 try:
-    urllib.request.urlretrieve(url, 'input.pdb')
-    print(f'Downloaded from {url}')
+    import boto3
+    from botocore.client import Config
+    s3 = boto3.client('s3',
+        endpoint_url=endpoint,
+        aws_access_key_id=os.environ.get('AWS_ACCESS_KEY_ID', ''),
+        aws_secret_access_key=os.environ.get('AWS_SECRET_ACCESS_KEY', ''),
+        config=Config(signature_version='s3v4'),
+        region_name='us-east-1'
+    )
+    s3.download_file(bucket, key, 'input.pdb')
+    print(f'Downloaded via boto3 ({os.path.getsize(\"input.pdb\")} bytes)')
+except ImportError:
+    print('boto3 not available, trying urllib with signing...')
+    # Fallback: use subprocess to call python with hmac signing
+    import urllib.request, hmac, hashlib, datetime
+    access_key = os.environ.get('AWS_ACCESS_KEY_ID', '')
+    secret_key = os.environ.get('AWS_SECRET_ACCESS_KEY', '')
+    if access_key and secret_key:
+        # Simple S3 GET with AWS Signature V2
+        date_str = datetime.datetime.utcnow().strftime('%a, %d %b %Y %H:%M:%S GMT')
+        string_to_sign = f'GET\n\n\n{date_str}\n/{bucket}/{key}'
+        signature = hmac.new(secret_key.encode(), string_to_sign.encode(), hashlib.sha1)
+        import base64
+        sig_b64 = base64.b64encode(signature.digest()).decode()
+        url = f'{endpoint}/{bucket}/{key}'
+        req = urllib.request.Request(url)
+        req.add_header('Date', date_str)
+        req.add_header('Authorization', f'AWS {access_key}:{sig_b64}')
+        with urllib.request.urlopen(req) as resp:
+            with open('input.pdb', 'wb') as f:
+                f.write(resp.read())
+        print(f'Downloaded via signed URL ({os.path.getsize(\"input.pdb\")} bytes)')
+    else:
+        print('No AWS credentials available')
+        sys.exit(1)
 except Exception as e:
-    print(f'Failed: {e}')
+    print(f'Download failed: {e}')
+    sys.exit(1)
 " >> run.log 2>&1
             if [ -f input.pdb ] && [ -s input.pdb ]; then
-                echo "Downloaded via python (\$(wc -c < input.pdb) bytes)" >> run.log
+                echo "S3 download successful (\$(wc -c < input.pdb) bytes)" >> run.log
                 PDB_FILE="input.pdb"
             else
-                echo "Python download failed" >> run.log
+                echo "S3 download failed" >> run.log
                 rm -f input.pdb
             fi
         fi