Chains and heterogens:
PDB Chain Sequences:
>1fn6A (A:) ivggytcaansipyqvslnsgshfcggslinsqwvvsaahcyksriqvrlgehnidvleg neqfinaakiithpnfngntldndimliklsspatlnsrvatvslprscaaagteclisg wgntkssgssypsllqclkapvlsnssckssypgqitgnmicvgflqggkdscqgdsggp vvcngqlqgivswgygcaqknkpgvytkvcnyvnwiqqtiaan