... ribozyme in Mn2+is that binding of the cosubstrate to its site induces a conformationalchange in the RNA that inhibits Mn2+binding atanother inhibitory site(s). It may be relevant that in vitro-evolved ... trans-reaction [10] that involves the free intron reacting with 5.8S rRNA (not shown). Together, these data sugges-ted that inhibition by Mn2+probably involved the core ribozyme, and not the intron ... sites. Hence, it may be that they bind to the samebasic locations, but that Mn2+binds with slightly dif-ferent configurations at some key sites, resulting in inhibition. In this respect, it...