From Biology to Biotechnology: Disulfide Bond Formation in Escherichia coli

Abstract

Disulfide bonds formed between a pair of oxidized cysteines are important to the structural integrity and proper folding of many proteins. Accordingly, Nature has evolved several sys- tems for the genesis and maintenance of such bonds. Beginning with the discovery of protein disulfide isomerase, which provided the first evidence for enzyme-catalyzed disulfide-bond formation, many years of research have resulted in the explication of the complex network of electron transport pathways needed for this process. Herein, we take a historical approach in describing the elucidation of disulfide-bond formation in E. coli. We frame this topic in the context of genome sequencing eras. The first section describes the discovery of eukaryotic protein disulfide isomerase and the subsequent research that followed from the early 1960s to the early 1990s, a time period we have named the pre-genomic sequencing era. The second section details the renaissance in research on disulfide-bond formation in the periplasm of prokaryotes, fueled by bacterial genetic screens and the development of genomic sequenc- ing technology. Accordingly, we have named this section the genomic sequencing era, which ranges from the early 1990s to approximately 2010. The final section outlines the use of bac- terial genetic screens to select for new oxidoreductase enzymes and their potential uses in biotechnological and pharmaceutical applications. This era we have dubbed the post-genomic sequencing era, and we envision it to represent the future of research on oxidative folding.