Just now PR updation is started. You may loss your PR initially but you'll gain again after a week... Don't worry!!!
Pagerank is not just important for link sellers, but it is important for SEO as well. Directly from Google @: http://www.google.com/corporate/tech.html I was just pointing out that your internal link structure is not optimized. If your position in the serps is good, I would not touch it either.