waston crick				reverse waston crick			hoogsteen			reverse hoogsteen	
AT	N6 - O4	N1 - N3			N6 - O2	N1 - N3		N6 - O4	N7 - N3		N6 - O2	N7 - N3
GC	O6 - N4	N1 - N3	N2 - O2		N1 - O2	N2 - N3		O6 - N4	N7 - N3		N/A	N/A