query about 3D structure

I read about your server I-TASSER & LOMETS. I am working as research scholar in molecular biology lab. My topic of research is related to polyketide synthase. I want to predict 3D structure of my protein sequence, so i tried using I-Tasser. But unfortunately, my protein is aroun 2000a.a as it includes different domains(motifs), but i guess the server doesnt accept large amino acid residues. Can you help?

My another query is when i take domain of my protein sequence and try to predict 3D structure, i am unable to do that. Now the query sequence is ok that is around 400a.a. But i want to view its 3D structure, is there any option in your server by which i can view the model??

I will be grateful if you can provide me some information as i am stuck badly.