... engineered ribozyme for RNA sequence exchangeFEBS Journal 272 (2005) 44644474 ê 2005 FEBS 4465 Efficient RNA ligation by reverse-joined hairpin ribozymes and engineering of twin ribozymes consisting of conventional ... site-specific alteration of RNA sequence is demonstrated.Results RNA ligation by reverse-joined hairpin ribozymes Reverse-joined hairpin ribozymes, first introduced by Ohtsuka and colleagues [29,30], ... variants of atandem configured hairpin ribozyme. Experimental proceduresSynthesis of ribozymes and substrates Reverse-joined hairpin ribozymes HPRJWTAn (n ẳ 6, 7,8, 12) and the twin ribozyme...