Chains and heterogens:
PDB Chain Sequences:
>2ctb_ (-) arstntfnyatyhtldeiydfmdllvaehpqlvsklqigrsyegrpiyvlkfstggsnrp aiwidlgihsrewitqatgvwfakkftedygqdpsftaildsmdifleivtnpdgfafth sqnrlwrktrsvtssslcvgvdanrnwdagfgkagassspcsetyhgkyansevevksiv dfvkdhgnfkaflsihsysqlllypygyttqsipdktelnqvaksavealkslygtsyky gsiittiyqasggsidwsynqgikysftfelrdtgrygfllpasqiiptaqetwlgvlti mehtlnn