You have discovered a novel self-cleaving catalytic RNA that cleaves the phosphodiester linkage between B-1 and B+1. Here is a summary of some of the data you have collected:

• Rates of cleavage are severely reduced when using cobalt hexamine instead of magnesium.

• Substitution of a guanosine positioned near the cleavage site with inosine lowers the overall rate.

• A cytosine residue positioned near the cleavage site has a perturbed N3 pKa near 7.0.

Draw a reasonable chemical mechanism (with proper arrows illustrating flow of electrons at each step) for cleavage of the bond between B-1 and B+1 using all of the available information. A complete answer requires you to draw a phosphodiester backbone; you may just use B for the bases at the -1 and +1 positions. In addition to the drawing, explain your mechanism in words making it clear how you used all of the data provided.