>3r50A (A:) observed residues (from ATOM records)
alqlaahsdarsgpvgsnggqfwsfrpvrplnkivlsfsgspdqtlnlisitfssnptdi
itvggvgpepltytetvnidgdiieisgmianykgynvirsikfttnkkeygpyganagt
pfnikipdgnkivgffgnsgwyvdaigayytak