Cytosine
It won't be possible. The two purines cannot fit together in DNA. However, if by defying the natural laws inhibited by the DNA structure and adenine somehow binds with guanine, the resulting DNA...
cytosine
thymine
Binding Off Fundamentals
Learn how to Get Snowboard Bindings
How to Use a Bias Tape Maker for Binding on a Quilt
Learn how to Select Ski Bindings