The Three-dimensional Structure of Hammerhead Ribozymes

摘要

Ribonucleic acids (RNA) that can catalyze chemical reactions have been the subject of intensive research ever since their discovery some thirteen years ago Ribozymes-RNA molecules with a defined base sequence and three-dimensional structure-recognizecertain RNA-sequences (substrates) in a base-specific manner and cleave a defined phosphoester bond of a defined base triplet In naturally occurring ribozymes this step is essential, as for instance in the reproduction (replication) of certain satelliteRNAs and yiroids. In these cases, the ribozyme and substrate sequences are found on the same RNA strand, leading to an intramolecular, in-cis cleavage However, ribozymes can also act intermolecularly (in-trans cleavage), with the result that they can betailored to cleave any desired substrate RNA selectively, thereby inactivating it biologically. This explains the great importance that molecular biologists and biochemists attach to this class of substances today, and that in the Song term makes therapeutic applications in vivo conceivable.