Need help with modeling on simbiology!!

Hi,

I have a protein which only gets activated when three different binding sites on DNA are all bound; however, the three sites are independent and interacting (so binding on one site affects binding in the next one differently).. I've attached a picture that might help to see the three layers of reactions (or it might be just confusing, in which case, you can just ignore it!)

I'm trying to do a parameter scan to find cooperativity in this system, but I'm kind of stuck... I don't know how to figure out the values for the binding constants in such as way as to achieve cooperativity? Is it mostly guess and check or am I missing something in simbiology that I can use the help me find the cooperativity factor?

If something is unclear, please ask and I will try to answer it best I can!

[pfb]

You have attached no picture.

Anyway, this is a matlab forum. How is this related to matlab?