CoV E - Coronavirus Envelop Protein E
Viral Fusion Pores
Three distinct classes of viral membrane fusion proteins have been identified based on structural criteria. Viral fusion proteins also contain different types of fusion peptides and vary in their reliance on accessory proteins. Despite the rich diversity of existent fusion proteins, all characterized viral fusion proteins convert from a fusion-competent state (dimers or trimers) to a membrane-embedded homotrimeric prehairpin, to a trimer-of-hairpins that brings the fusion peptide, attached to the target membrane, and the transmembrane domain, attached to the viral membrane, into close proximity, thereby facilitating the union of viral and target membranes. During these conformational conversions, the fusion proteins induce membranes to progress through stages of close apposition, hemifusion, and then the formation of small, and finally large, fusion pores.
CoV E Background Information
Coronaviruses are large, often spherical, enveloped, single-stranded positive-sense RNA viruses, ranging in size from 80-220 nm. Of the four structural proteins encoded in the viral genome, the RNA winds around the highly basic nucleocapsid (N) protein. The three other structural proteins, envelope (E), membrane (M) and spike (S), are transmembrane proteins. The E protein is a small (9-12 kDa) single transmembrane domain protein, which enables virus assembly with the M protein, a larger (23-35 kDa) 3TM protein.
The channel activity was first demonstrated for CoV E in planar lipid bilayers, where it was found that a synthetic peptide corresponding to the protein could permeabilize bilayers to Na+ and K+, with a 10-fold preference for Na+. The role of the CoV E ion channel in infection is not entirely clear. However, studies have linked the putative ion channel activity with virus replication and release.
UniProt: P0DTC4 (Severe acute respiratory syndrome coronavirus 2 (2019-nCoV) (SARS-CoV-2))
Coronavirus envelope (CoV E) proteins are ~100-residue polypeptides with at least one channel-forming α-helical transmembrane (TM) domain. The extramembrane C terminal tail contains a completely conserved proline, at the center of a predicted β coil β motif.
Plays a central role in virus morphogenesis and assembly. Acts as a viroporin and self-assembles in host membranes forming pentameric protein-lipid pores that allow ion transport. Also plays a role in the induction of apoptosis
MYSFVSEETG TLIVNSVLLF LAFVVFLLVT LAILTALRLC AYCCNIVNVS LVKPSFYVYS RVKNLNSSRV PDLLV
Bilayer Recordings on the Orbit Product family or on the Port-a-Patch
Reviews and Links
- White et al. (2008) Structures and Mechanisms of Viral Membrane Fusion Proteins. Multiple Variations on a Common Theme. Crit Rev Biochem Mol Biol. 43(3): 189–219.
Transporter classification database:
- Envelope small membrane protein (E, Severe acute respiratory syndrome coronavirus 2 (2019-nCoV) (SARS-CoV-2))