>1a21A (A:) observed residues (from ATOM records) tgraynltwkstnfktilewepksidhvytvqistrlenwkskcfltaetecdltdevvk dvgqtymarvlsyparnttgfpeeppfrnspeftpyldtnlgqptiqsfeqvgtklnvtv qdartlvtflslravfgkdlnytlyywrkktattntneflidvdkgenycfsvqavipsr krkqrspesltect