Functional studies on the severe acute respiratory syndrome coronavirus envelope protein.

Abstract

The envelope protein of severe acute respiratory syndrome coronavirus is a small membrane protein, with poorly defined roles in viral infection and life cycle. Recent studies have indicated its multiple functions. Beyond the conventional recognized role in virion assembly and budding, E protein also has ion channel activity, and may be involved in host stress response or host-protein interactions. However, how these

functions are related to infectivity still remains debated. In this study we propose a new function of E protein, which is to induce membrane fusion, based on the observation of structural similarities with identified viral fusion peptides. We also examined the ion transport activity based on fluorescence indicator to validate the feasibility of liposome-based high-throughput screening assay for E protein inhibitor discovery. The fusion activity was unfortunately not observed, while the screening

assay based on ion transport had been validated, with several potential hits identified.