Thank you very much for you answer.

My english is not very well,Because I just come from china.

My major subject is gene structure,So I am not good at protein structure.

But ,I think this is very useful for me to analyze protein structure and asure their structure.

So,I must thank for you first!

You means:

If I get a homologous model structure from swissmodel which I just align with PDB stucture,i must minimize structure ,at firstĄŁ

But before i do minimization,I should add water or not.so this is a question.Which condition should I add water?

Secondly,I get a stable structure after minimization.If I want to do mutation, I should do minimization for every time mutation about this structure.

Thank you very much!