Does guanine have two binding sites as compared to the other nitrogenous bases??
Please clarify what you mean by binding site. Guanine does have two sites that it can bind (hydrogen bonds) to cytosine with when it is in DNA. Hope this is the binding you were looking for.
I think there are 3 hydrogen bonds between guanine and cytosine, and 2 hydrogen bonds between adenine and thymine.
whizzbee is right
http://projects.cbe.ab.ca/Diefenbaker/B … mage35.gif