they've sided with the US and didn't help them during the reovlution so they may have serious grounds for concerns. Iran has a historical beef with the US (and their shas) and the US doesn't easily forget it's failures - eg Cuba, and Iran. However China wasn't that much interested in securing global interests back then and that has changed dramatically.
Fire in Jerusalem suburb causes severe air pollution (Haaretz)
from the article: Netanyahu: WikiLeaks cables prove Israel is right on Iran