complementary oligonucleotides with 5 ' overhanging deoxyguanosine or deoxycytidine stretches , respectively , of the general form 5'-d ( gggcaaraac ) .5'-d ( cccgttyttg ) , where r represents the bases adenine ( a ) , hypoxanthine ( base of inosine nucleoside , i ) , purine ( r ) , 2-aminopurine ( n2r ) , or 2,6-diaminopurine ( n2,6 ( 2 ) r ) and where y represents the pyrimidine bases thymine ( t ) or cytosine ( c ) , have been chemically synthesized .
C0001407
adenine
C0000263
2-aminopurine