Chains and heterogens:
PDB Chain Sequences:
>1b4pA (A:) pmilgywnvrglthpirllleytdssyeekryamgdapdydrsqwlnekfklgldfpnlp ylidgsrkitqsnaimrylarkhhlcgeteeerirvdvlenqamdtrlqlamvcyspdfe rkkpeyleglpekmklyseflgkqpwfagnkityvdflvydvldqhrifepkcldafpnl kdfvarfeglkkisdymksgrflskpifakmafwnpk