Ideal helices

Hi, I'm modelling G-protein coupled receptors using rhodopsin as a template.

When I compare the Ramachandran plot of the models vs that of rhodopsin,

the models have much more ideal helices than the rhodopsin X-ray structure (2.8 A). Is this because: 1) The homology is relatively low (20-30%) and the distance constraints receive a low weight in the pdf function?? 2) The helices in rhodopsin are less regular than the globular proteins used in the pdf parametrization?? 3) None of the above...

Sincerely, Dan

-- Dan Thomas Major (at Dr. B. Fischer's lab) Bar-Ilan University Ramat-Gan, Israel Phone: 972-3-5317785 Fax: 972-3-5348730