Tryptophan Biosynthesis in Escherichia coli

Abstract

Investigations employing mutant bacteria and bacteriophage have provided considerable insight into the effects of mutations on protein structure, the types of alterations of genetic material which constitute mutations, how genetic material specifies protein structure, and the nature of the genetic code. In addition, mutational studies have revealed interesting and important aspects of the relationship between structure and function in proteins. The mutational approach has also been rewarding in studies of regulatory mechanisms and genetic elements involved in regulatory processes. Finally, mutational studies are being employed in the examination of the assumptions underlying current concepts of molecular evolution. It is evident from this partial list that the mutational approach is applicable to the study of a wide range of biological phenomena. The unique feature responsible for its efficacy is that it permits the examination of the consequences of inactivation of a single gene product. This enables the investigator to determine the