Autor(es): Sánchez-San Martín Claudia, Nanda Soumya, Zheng Yan, Fields Whitney, Kielian Margaret

Resumo: Alphaviruses are small enveloped RNA viruses that include important emerging human pathogens, such as chikungunya virus (CHIKV). These viruses infect cells via a low-pH-triggered membrane fusion reaction, making this step a potential target for antiviral therapies. The E1 fusion protein inserts into the target membrane, trimerizes, - refolds to a hairpin-like conformation in which the combination of E1 domain III (DIII) - the stem region (DIII-stem) pack against a core trimer composed of E1 domains I - II (DI/II). Addition of exogenous DIII proteins from Semliki Forest virus (SFV) has been shown to inhibit E1 hairpin formation - SFV fusion - infection. Here we produced - characterized DIII - DI/II proteins from CHIKV - SFV. Unlike SFV DIII, both core trimer binding - fusion inhibition by CHIKV DIII required the stem region. CHIKV DIII-stem - SFV DIII-stem showed efficient cross-inhibition of SFV, Sindbis virus, - CHIKV infections. We developed a fluorescence anisotropy-based assay for the binding of SFV DIII-stem to the core trimer - used it to demonstrate the relatively high affinity of this interaction (Kd [dissociation constant], ?85 nM) - the importance of the stem region. Together, our results support the conserved nature of the key contacts of DIII-stem in the alphavirus E1 homotrimer - describe a sensitive - quantitative in vitro assay for this step in fusion protein refolding.

Imprenta: Journal of Virology, v. 87, n. 13, p. 7680-7687, 2013

Identificador do objeto digital: 10.1128/JVI.00814-13

Descritores: Chikungunya virus - Biosynthesis ; Chikungunya virus - Cell ; Chikungunya virus - Proteins ; Chikungunya virus - RNA ; Chikungunya virus - Viral infections ; Chikungunya Virus - Virus

Data de publicação: 2013