Chains and heterogens:
PDB Chain Sequences:
>1fr1A (A:) aakteqqiadivnrtitplmqeqaipgmavaiiyqgkpyyftwgkadiannrpvtqqtlf elgsvsktfngvlggdaiargeiklsdpvtqywpeltgkqwqgisllhlatytagglplq vpddvtdkaallrfyqnwqpqwapgakrlyanssiglfgalavkpsgmsyeeamskrvlh plklahtwitvpqseqkdyawgyregkpvhvspgqldaeaygvkssvidmtrwvqanmda sqvqektlqqgielaqsrywrigdmyqglgwemlnwpvkadsiisgsdskvalaalpave vnppapavkaswvhktgstggfgsyvafvpeknlgivmlanksypnpvrveaawrilekl q
>1fr1B (B:) aakteqqiadivnrtitplmqeqaipgmavaiiyqgkpyyftwgkadiannrpvtqqtlf elgsvsktfngvlggdaiargeiklsdpvtqywpeltgkqwqgisllhlatytagglplq vpddvtdkaallrfyqnwqpqwapgakrlyanssiglfgalavkpsgmsyeeamskrvlh plklahtwitvpqseqkdyawgyregkpvhvspgqldaeaygvkssvidmtrwvqanmda sqvqektlqqgielaqsrywrigdmyqglgwemlnwpvkadsiisgsdskvalaalpave vnppapavkaswvhktgstggfgsyvafvpeknlgivmlanksypnpvrveaawrilekl q