
Cover Illustration: Protein Data Bank code 488d; RNA ribozyme strand: ribbon-stick representation, brown; uncleaved RNA substrate: ribbon-stick representation, green; cadmium ions: brown balls. The image was generated with ViewerLite from Accelrys, Inc. Cover image provided by IMB Jena Image Library of Biological Macromolecules (www.imb-jena.de/IMAGE.html).