A structural analysis of M protein in coronavirus assembly and morphology

Abstract

The M protein of coronavirus plays a central role in virus assembly, turning cellular membranes into workshops where virus and host factors come together to make new virus particles. We investigated how M structure and organization is related to virus shape and size using cryo-electron microscopy, tomography and statistical analysis. We present evidence that suggests M can adopt two conformations and that membrane curvature is regulated by one M conformer. Elongated M protein is associated with rigidity, clusters of spikes and a relatively narrow range of membrane curvature. In contrast, compact M protein is associated with flexibility and low spike density. Analysis of several types of virus-like particles and virions revealed that S protein, N protein and genomic RNA each help to regulate virion size and variation, presumably through interactions with M. These findings provide insight into how M protein functions to promote virus assembly.

Analysis of antigenicity and pathogenicity reveals major differences among QX-like infectious bronchitis viruses and other serotypes

“…Alternatively, some of the distinct amino acid sites in the other structural proteins may have a positive influence on the pathogenicity of the two strains. There are 1 and 0 different amino acid sites in E and M proteins, respectively, suggesting that these proteins may not be directly linked with virulence, as has been suggested earlier (Neuman, 2011;Sapats and Wright, 1996). Clearly, more studies are needed to explore the function of these amino acids.…”

A potential role for integrins in host cell entry by SARS-CoV-2

“…Schematic representation of SARS coronavirus virion(Hulo et al, 2011), based on cryo-electron microscopy(Neuman et al, 2011).https://doi.org/10.1016/j.antiviral.2020.104759 Received 20 February 2020; Received in revised form 26 February 2020; Accepted 28 February 2020…”

Characterization of an Immunodominant Epitope in the Endodomain of the Coronavirus Membrane Protein

“…M protein self-interactions occur among the transmembrane domains [49,50]. The ectodomain of the CoV M protein plays an important role in interactions with other viral proteins, such as the N protein of MHV [51,52,53], SARS-CoV [54,55,56], and TGEV [28] and the S protein of MHV [25] and SARS-CoV [13].…”