The M Protein of SARS-CoV: Basic Structural and Immunological Properties

Hu, Yongwu; Wen, Jie; Tang, Lin; Zhang, Haijun; Zhang, Xiaowei; Li, Yan; Wang, Jing; Han, Yujun; Li, Guoqing; Shi, Jianping; Tian, Xiangjun; Jiang, Feng; Zhao, Xiaoqian; Wang, Jun; Liu, Siqi; Zeng, Changqing; Wang, Jian; Yang, Huanming

Several predicted features are related to the TM region of the M protein. The predicted signal peptide has a structure and position similar to the M protein in other coronaviruses, posing a question as to whether it is actually cleaved and released. The cleavage site (AYS-NR, between Codons 39 and 40) may be found within the first inter-TM segment (12 residues between Codons 37-50), which is very likely to be in the interior, thus reducing the possibility of cleavage by any cellular proteinase activities outside the virion. However, the possibility of the cleavage and release before viral assembly or after membrane fusion should be considered.