Chains and heterogens:
PDB Chain Sequences:
>1b31A (A:) easvsidakfkahgkkylgtigdqytltkntknpaiikadfgqltpensmkwdatepnrg qftfsgsdylvnfaqsngklirghtlvwhsqlpgwvssitdkntlisvlknhittvmtry kgkiyawdvlneifnedgslrnsvfynvigedyvriafetarsvdpnaklyindynldsa gyskvngmvshvkkwlaagipidgigsqthlgagagsavagalnalasagtkeiaiteld iagasstdyvnvvnaclnqakcvgitvwgvadpdswrsssspllfdgnynpkaaynaian al