The M protein of SARS-CoV: basic structural and immunological properties.
We studied structural and immunological properties of the SARS-CoV M (membrane) protein, based on comparative analyses of sequence features, phylogenetic investigation, and experimental results. The M protein is predicted to contain a triple-spanning transmembrane (TM) region, a single N-glycosylation site near its N-terminus that is in the exterior of the virion, and a long C-terminal region in the interior. The M protein harbors a higher substitution rate (0.6% correlated to its size) among viral open reading frames (ORFs) from published data. The four substitutions detected in the M protein, which cause non-synonymous changes, can be classified into three types. One of them results in changes of pI (isoelectric point) and charge, affecting antigenicity. The second changes hydrophobicity of the TM region, and the third one relates to hydrophilicity of the interior structure. Phylogenetic tree building based on the variations of the M protein appears to support the non-human origin of SARS-CoV. To investigate its immunogenicity, we synthesized eight oligopeptides covering 69.2% of the entire ORF and screened them by using ELISA (enzyme-linked immunosorbent assay) with sera from SARS patients. The results confirmed our predictions on antigenic sites.
Hu
Yongwu
Y
Beijing Genomics Institute, Chinese Academy of Sciences, Beijing 101300, China.
Wen
Jie
J
Tang
Lin
L
Zhang
Haijun
H
Zhang
Xiaowei
X
Li
Yan
Y
Wang
Jing
J
Han
Yujun
Y
Li
Guoqing
G
Shi
Jianping
J
Tian
Xiangjun
X
Jiang
Feng
F
Zhao
Xiaoqian
X
Wang
Jun
J
Liu
Siqi
S
Zeng
Changqing
C
Wang
Jian
J
Yang
Huanming
H
D000595:Amino Acid Sequence; D001483:Base Sequence; D016000:Cluster Analysis; D000086862:Coronavirus M Proteins; D004797:Enzyme-Linked Immunosorbent Assay; D007118:Immunoassay; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics*; D009842:Oligopeptides; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D045473:Severe acute respiratory syndrome-related coronavirus / Q000235:genetics*; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D014763:Viral Matrix Proteins / Q000737:chemistry / Q000235:genetics* / Q000276:immunology*
D000086862:Coronavirus M Proteins; C000706237:M protein, SARS-CoV; D009842:Oligopeptides; D014763:Viral Matrix Proteins