REPRESENTATION OF THE SECONDARY AND TERTIARY STRUCTURE OF GROUP-I INTRONS

Group I introns, which are widespread in nature, carry out RNA self-sp licing. The secondary structure common to these introns was for the mo st part established a decade ago. Information about their higher order structure has been derived from a range of experimental approaches, c omparative sequence analysis, and molecular modelling. This informatio n now provides the basis for a new two-dimensional structural diagram that more accurately represents the domain organization and orientatio n of helices within the intron, the coaxial stacking of certain helice s, and the proximity of key nucleotides in three-dimensional space. It is hoped that this format will facilitate the detailed comparison of group I intron structures.