📄 Negatively charged residues in the endodomain are critical for specific assembly of spike protein into murine coronavirus

Coronavirus spike (S) protein assembles into virions via its carboxy-terminus, which is composed of a transmembrane domain and an endodomain. Here, the carboxy-terminal charge-rich motif in the endodomain was verified to be critical for the specificity of S assembly into mouse hepatitis virus (MHV). Recombinant MHVs exhibited a range of abilities to accommodate the homologous S endodomains from the betacoronaviruses bovine coronavirus and human SARS-associated coronavirus, the alphacoronavirus porcine transmissible gastroenteritis virus (TGEV), and the gammacoronavirus avian infectious bronchitis virus respectively. Interestingly, in TGEV endodomain chimeras the reverting mutations resulted in stronger S incorporation into virions, and a net gain of negatively charged residues in the charge-rich motif accounted for the improvement. Additionally, MHV S assembly could also be rescued by the acidic carboxy-terminal domain of the nucleocapsid protein. These results indicate an important role for negatively charged endodomain residues in the incorporation of MHV S protein into assembled virions. © 2013.

keywords 🔗 bovine coronavirus (221) 🔗 bronchitis virus (233) 🔗 hepatitis virus (437) 🔗 mouse hepatitis (371) 🔗 avian infectious (53) 🔗 important role (140) 🔗 nucleocapsid protein (162) 🔗 gastroenteritis virus (188) 🔗 transmembrane domain (51) 🔗 infectious bronchitis (235) 🔗 results indicate (178) 🔗 transmissible gastroenteritis (226)

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