Path D - Module 29: PDB Bioassemblies & AltLocs

Membrane crystals are notoriously messy. In this module, you will learn to use make_bioassembly() to generate the full functional tetramer of a channel from a single asymmetric chain. PDB paths and PDB text share the native PDBFileHandler, which retains canonical alternate-location sites, explicit connectivity, formal charge, and REMARK 350 operators for every native target. Generated copies receive unique uppercase chain_id values, continuing with AA, AB, and so on after Z, while author-provided chain_name values remain unchanged and may repeat.

import molsysmt as msm
molsys = msm.convert('pdb:1K4C', to_form='molsysmt.MolSys')
full_tetramer = msm.build.make_bioassembly(molsys)

print(f"Tetramer built with {msm.get(full_tetramer, element='chain', n_chains=True)} chains.")

Tetramer built with 60 chains.