>1xc4A (A:) observed residues (from ATOM records)
meryeslfaqlkerkegafvpfvtlgdpgieqslkiidtlieagadalelgipfvtpaqc
femlalirekhptipigllmyanlvfnkgidefyarcekvgvdsvlvadvpveesapfrq
aalrhnvapificppnadddllrqiasygrgytyllsragaalplnhlvaklkeynaapp
lqgfgisapdqvkaaidagaagaisgsaivkiieqhinepekmlaalkvfvqpmkaatrs