The baculovirus expression system has been widely used to produce the capsid proteins of Norovirus (NV) and the proteins form virus-like particles (VLPs) that are useful in many studies, such as immunology, diagnosis, and host-receptor interaction. We report here the application of the E. coli expression system in the production of recombinant NV capsid proteins. In a direct comparison of a previous well-characterized NV strain (VA387), we have demonstrated that the E. coli-expressed capsid proteins maintain the same antigenicity and receptor binding specificity as that of the baculovirus-expressed capsid, although the E. coli-expressed VA387 proteins did not form VLPs. Using the E. coli-expression system, we characterized the receptor-binding patterns of three additional NV strains (OIF1998, Parris Island and VA115), in which OIF1998 binds to HBGA of nonsecretors but did not bind or binds weakly to the HBGA of secretors, as seen in strain VA207. Parris Island binds to HBGA of types A and B but not type O secretors and nonsecretors. VA115 did not show specific binding to any A, B, O secretor nor nonsecretor, which is also observed when the capsid protein of this strain was expressed in baculovirus. Our data indicate that VLP formation is not required for receptor binding, and that the bacteria expression system offers a simple alternative for large production of NV capsid protein for various research purposes, particularly for strains generating low yields in the insect cells. 相似文献
Summary: Novel temperature sensitive poly(N‐isopropylacrylamide‐co‐acryloyl beta‐cyclodextrin) (P(NIPA‐co‐A‐CD)) hydrogels with fast shrinking rates were prepared by radical polymerization of NIPA, A‐CD and crosslinker in a mixture of water/1,4‐dioxane as solvent. Because the mixed solvent was a poor solvent for the copolymers, phase separation occurred during the polymerization, which resulted in a heterogeneous, porous structure of the hydrogels. In contrast to the normal PNIPA hydrogel and the homo P(NIPA‐co‐A‐CD) gel prepared in water, the P(NIPA‐co‐A‐CD) hydrogels synthesized in water/1,4‐dioxane as solvent exhibited higher swelling ratios at the temperature below the lower critical solution temperature (LCST) and shrunk rapidly to equilibrium within shorter time when the temperature was increased above LCST. Increasing the acryloyl beta‐cyclodextrin content in the gels led to a slight decrease of the swelling ratio at lower temperature and had no marked influence on the shrinking kinetics. The gels prepared in water/1,4‐dioxane, at different v/v ratios of 1.0/0.2, 0.8/0.4 and 0.6/0.6, showed similar properties.
SEM photos of the heterogeneous P(NIPA‐co‐A‐CD) hydrogel prepared in water/1,4‐dioxane. 相似文献