Biochemical evidence for the prese of the severe acute respiratory protein expressed nce of mixed membrane topologies syndrome coronavirus envelope in mammalian cells
Authors: Yuan, Q.; Liao, Y.; Torres, J.; Tam, J. P.; Liu, D. X.
Coronavirus envelope (E) protein is a small integral membrane protein with multi-functions in virion assembly, morphogenesis and virus-host interaction. Different coronavirus E proteins share striking similarities in biochemical properties and biological functions, but seem to adopt distinct membrane topology. In this report, we study the membrane topology of the SARS-CoV E protein by immunofluorescent staining of cells differentially permeabilized with detergents and proteinase K protection assay. It was revealed that both the N- and C-termini of the SARS-CoV E protein are exposed to the cytoplasmic side of the membranes (NcytoCcyto). In contrast, parallel experiments showed that the E protein from infectious bronchitis virus (113) spanned the membranes once, with the N-terminus exposed luminally and the C-terminus exposed cytoplasmically (N-exo(lum)-C-cyto). Intriguingly, a minor proportion of the SARS-CoV E protein was found to be modified by N-linked glycosylation on Asn 66 and inserted into the membranes once with the C-terminus exposed to the luminal side. The presence of two distinct membrane topologies of the SARS-CoV E protein may provide a useful clue to the pathogenesis of SARS-CoV. (c) 2006 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.
Analysis of the Genome Sequence and Prediction of B-Cell Epitopes of the Envelope Protein of Middle East Respiratory Syndrome-Coronavirus
IEEE-ACM TRANSACTIONS ON COMPUTATIONAL BIOLOGY AND BIOINFORMATICS
Authors: Xie, Qian; He, Xiaoyan; Yang, Fangji; Liu, Xuling; Li, Ying; Liu, Yujing; Yang, ZhengMeng; Yu, Jianhai; Zhang, Bao; Zhao, Wei
The outbreak of Middle East respiratory syndrome-coronavirus (MERS-CoV) in South Korea in April 2015 led to 186 infections and 37 deaths by the end of October 2015. MERS-CoV was isolated from the imported patient in China. The envelope (E) protein, a small structural protein of MERS-CoV, plays an important role in host recognition and infection. To identify the conserved epitopes of the E protein, sequence analysis was performed by comparing the E proteins from 42 MERS-CoV strains that triggered severe pandemics and infected humans in the past. To predict the potential B cell epitopes of E protein, three most effective online epitope prediction programs, the ABCpred, Bepipred, and Protean programs from the LaserGene software were used. All the nucleotides and amino acids sequences were obtained from the NCBI Database. One potential epitope with a suitable length (amino acids 58-82) was confirmed and predicted to be highly antigenic. This epitope had scores of >0.80 in ABCpred and level 0.35 in Bepipred programs. Due to the lack of X-ray crystal structure of the E protein in the PDB database, the simulated 3D structure of the E protein were also predicted using PHYRE 2 and Pymol programs. In conclusion, using bioinformatics methods, we analyzed the genome sequence of MERS-CoV and identified a potential B-cell epitope of the E protein, which might significantly improve our current MERS vaccine development strategies.