>1g21A (A:) observed residues (from ATOM records)
sreevesliqevlevypekarkdrnkhlavndpavtqskkciisnkksqpglmtirgcay
agskgvvwgpikdmihishgpvgcgqysragrrnyyigttgvnafvtmnftsdfqekdiv
fggdkklaklidevetlfplnkgisvqsecpigligddiesvskvkgaelsktivpvrce
gfrgvsqslghhiandavrdwvlgkrdedttfastpydvaiigdyniggdawssrillee
mglrcvaqwsgdgsiseieltpkvklnlvhcyrsmnyisrhmeekygipwmeynffgptk
tieslraiaakfdesiqkkceeviakykpeweavvakyrprlegkrvmlyigglrprhvi
gayedlgmevvgtgyefahnddydrtmkemgdstllyddvtgyefeefvkrikpdligsg
ikekfifqkmgipfremhswdysgpyhgfdgfaifardmdmtlnnpcwkklqapwe