Concepts and tools to exploit the potential of bacterial inclusion bodies in protein science and biotechnology

Abstract

Cells have evolved complex and overlapping mechanisms to protect their proteins from aggregation. However, several reasons can cause the failure of such defences, among them mutations, stress conditions and high rates of protein synthesis, all common consequences of heterologous protein production. As a result, in the bacterial cytoplasm several recombinant proteins aggregate as insoluble inclusion bodies. The recent discovery that aggregated proteins can retain native-like conformation and biological activity has opened the way for a dramatic change in the means by which intracellular aggregation is approached and exploited. This paper summarizes recent studies towards the direct use of inclusion bodies in biotechnology and for the detection of bottlenecks in the folding pathways of specific proteins. We also review the major biophysical methods available for revealing fine structural details of aggregated proteins and which information can be obtained through these techniques. In the bacterial cytoplasm a number of recombinant proteins aggregate to form inclusion bodies. This first review is focused on the cellular events leading to aggregation and describes the biophysical techniques to reveal the structure of proteins within inclusion bodies. Since aggregated proteins can retain native-like structure and biological conformation, possible application in biotechnology is also discussed. © 2011 The Authors Journal compilation © 2011 FEBS.