[Biopython] Module Polypeptide

[stanam bharat]

Hi all

I am new to Python and Biopython.I am trying to extract sequence from PDB
file. As you stated in previous posts, i took help of biopdb_faq.pdf and
used polypeptide module.

In some PDB files like "3FCS" which has only 4 chains, but the resulting
sequence has 14 chain pieces.Why is it? Is this problem with PDB files? Can
I overcome this?

Thanks for your valuable time.
sincerely,
Bharat.