RNA-Helix-Destabilizing Proteins

Abstract

Publisher Summary This chapter presents a discussion on ribonucleic acid (RNA)-helix-destabilizing proteins. The chapter outlines some aspects of RNA metabolism where the need for helix-destabilizing proteins appears to be evident. The chapter focuses on ribosomal protein S1 from E. coli and protein HD40 from the brine shrimp Artemia salina , a major component of heterogeneous nuclear ribonucleoprotein (hnRNP) particles. In both cases, the in vitro unwinding activity of these proteins can be correlated with their respective functions. The chapter describes the nucleic acid binding and helix-destabilizing properties of protein S1 and HD40. While comparative investigations of analogous proteins from other eukaryotes are needed, HD40 may prove to be a good model for in vitro studies on the structure and function of hnRNP; its physical properties appear to be representative of the glycine-rich core proteins, and it can be purified in relatively large amounts. In contrast to helix-destabilizing proteins participating in dynamic processes that appear to exercise a transient effect on the conformation of the nucleic acid, HD40 is a component of an isolatable nucleoprotein in which the single-stranded RNA is maintained in an unfolded state owing to its interaction with the protein. The chapter recommends the need for in vitro investigations involving purified individual hnRNP proteins and messenger ribonucleic acid (mRNA) precursors along with the development of specific methods for the isolation of native hnRNP.