Cover photograph (Copyright © 2004, American Society for Microbiology. All Rights Reserved.): Crystal structure of TATA-binding protein (TBP; blue), TFIIA (green), and TFIIB (cyan) complexed with DNA (black) based on structures reported previously. Mutations in TBP that are lethal are shown in red or yellow. Site-directed mutations created on the TBP surface that eliminate interaction with TFIIB are shown in orange. (See related article on p. 6419.)