I am abit confused with PDB data, too many links there to find out what is going on with the file I'm interested with.
I downloaded the PDB file for a homologus protein in cow (3Qz1), it seems it has 4 chains in the structure and they all look identical . The enzyme is suppose to be monomeric AFAIK. Perhaps the crystal has 4 of them aggregated together. There is no paper on the structure released though.
So, if I would like to do homology modelling using Discovery studio, I have to do alignment first, but it seems the alignment command (human vs cow ) using the software showed that it aligned to only one of the chains.
Perhaps there is a command feature in DS that allow me to exclude the other 3 chains.
TIA for comments