1SUN:
reference: Monitoring of the cooperative unfolding of the sunY group I intron of bacteriophage T4. The active form of the sunY ribozyme is stabilized by multiple interactions with 3' terminal intron components., Jaeger L, Westhof E, Michel F, J Mol Biol 1993 Nov 20;234(2):331-46. PMID: 8230218

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