20 September 1996
Vol 273, Issue 5282

About The Cover

Experimental electron density map of the P4-P6 domain of the Tetrahymena thermophila group I intron contoured at 1.4 standard deviations above the mean. The 2.8-angstrom crystal structure of the 160-nucleotide domain reveals the close packing of RNA helices likely to be a common feature of ribozymes, the ribosome, and the spliceosome. See pages 1678 and 1696 and the related Perspective on page 1676. [Image: J. H. Cate and J. A. Doudna]