Chains and heterogens:
PDB Chain Sequences:
>1f20A (A:) swkrnkfrltyvaeapdltqglsnvhkkrvsaarllsrqnlqspkssrstifvrlhtngn qelqyqpgdhlgvfpgnhedlvnalierledappanhvvkvemleerntalgvisnwkde srlppctifqafkyyldittpptplqlqqfaslatnekekqrllvlskglqeyeewkwgk nptmvevleefpsiqmpatllltqlsllqpryysissspdmypdevhltvaivsyhtrdg egpvhhgvcsswlnriqaddvvpcfvrgapsfhlprnpqvpcilvgpgtgiapfrsfwqq rqfdiqhkgmnpcpmvlvfgcrqskidhiyreetlqaknkgvfrelytaysrepdrpkky vqdvlqeqlaesvyralkeqgghiyvcgdvtmaadvlkaiqrimtqqgklseedagvfis rlrddnryhedifgv