Abstract
In summary, our studies have resulted in the development of new reagents and synthetic procedures for the introduction of both radioactivity and photolability into antibiotics; have provided examples of how PAGE analysis can be used to conveniently test various aspects of photoaffinity labeling of complex receptors, such as the ribosome; have revealed examples of unexpected photoreactivity, as in the case of puromycin; and have provided strong evidence regarding the three-dimensional location of the peptidyl transferase center and the site of that interaction of the 3' and of aminoacyl-tRNA with the 30S subunit. Work that is now in progress should provide similar detailed information regarding other functional sites in the ribosome.