DNA-binding protein bound to DNA: how to have model use double-stranded DNA versus single-stranded DNA

One of the proteins that I submitted to i-TASSER is a DNA-binding sigma factor. In the final results page, under “ligand binding sites”, there is a model of this protein bound to nucleic acid.

When I click on model's reference PDB # to see the original crystal structure (an E. coli sigma factor bound to DNA), I noticed that the structure used as a reference for the i-TASSER model contains double stranded DNA (the E. coli model) – but the i-TASSER model only shows single stranded DNA. Is there a way to obtain the i-TASSER model with double stranded DNA? Or is there a trick to make the DNA double stranded in my final model?

I don’t know if this is of importance, but I’ve been using a software called Chimera out of UCSF to visualize the models.