These are available using the chnList, chnType and chn methods.
Usage:
chnList()
This will return a string of all the chain identifiers.
chnType()
This will return a list of the types of the different chains.
Returned types are: Protein, DNA, RNA, SOLVENT and HETERO.
chn(chainId="", hetSkip = 0)
chainId is one chain selection string consistent with the slection scheme previsouly detailed. e.g. ``-AC ``. Note that the blank
chain identifier is a valid identifier for the selection. An empty string will result in nothing returned.