Chains and heterogens:
PDB Chain Sequences:
>1exxA (A:) lspqleelitkvskahqetfpslcqlgkyttnssadhrvqldlglwdkfselatkciiki vefakrlpgftglsiadqitllkaacldilmlrictrytpeqdtmtfsdgltlnrtqmhn agfgpltdlvfafagqllplemddtetgllsaiclicgdrmdleepekvdklqeplleal rlyarrrrpsqpymfprmlmkitdlrgistkgaeraitlkmeipgpmppliremle