“…In addition, the effects of other base substitutions (1,16,18,22,26,29,31,33), abasic sites (22,29), mismatched base pairs (22,29,33), methylphosphonodiester substitution (21), and adduct interference (2) have been used to explore potentially important interactions between HIV-1 IN and viral U5 (2,16,18,21,22,26,29,31,33) or U3 (1,2,25) sequences during processing and DNA joining. Other INs have also been studied with altered substrates (6,10,13,23,24,28,30). However, general rules describing which viral DNA bases interact most critically with different integrases have not been defined.…”