RESUMO
Flexibility or rigidity of the linker between two fused proteins is an important parameter that affects the function of fusion proteins. In this study, we constructed a linker library with five elementary units based on the combination of the flexible (GGGGS) and the rigid (EAAAK) units. Molecular dynamics (MD) simulation showed that more rigid units in the linkers lead to more helical conformation and hydrogen bonds, and less distance fluctuation between the N- and C-termini of the linker. The diversity of linker flexibility of the linker library was then studied by fluorescence resonance energy transfer (FRET) of cyan fluorescent protein (CFP)-yellow fluorescent protein (YFP) fusion proteins, which showed that there is a wide range of distribution of the FRET efficiency. Dissipative particle dynamics (DPD) simulation of CFP-YFP with different linkers also gave identical results with that of FRET efficiency analysis, and we further found that the combination manner of the linker peptide had a remarkable effect on the orientation of CFP and YFP domains. Our studies demonstrated that the construction of the linker library with the widely controllable flexibility could provide appropriate linkers with the desirable characteristics to engineer the fusion proteins with the expected functions.
Assuntos
Fusão Gênica Artificial , Engenharia de Proteínas/métodos , Proteínas Recombinantes de Fusão/genética , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Transferência Ressonante de Energia de Fluorescência , Proteínas de Fluorescência Verde/química , Proteínas de Fluorescência Verde/genética , Proteínas Luminescentes/química , Proteínas Luminescentes/genética , Simulação de Dinâmica Molecular , Conformação Proteica , Proteínas Recombinantes de Fusão/químicaRESUMO
Clusters with diverse structures and functions have been used to create novel cluster-assembled materials (CAMs). Understanding their self-assembly process is a prerequisite to optimize their structure and function. Herein, two kinds of unlike organo-functionalized inorganic clusters are covalently linked by a short organic tether to form a dumbbell-shaped Janus co-cluster. In a mixed solvent of acetonitrile and water, it self-assembles into a crystal with a honeycomb superstructure constructed by hexagonal close-packed cylinders of the smaller cluster and an orderly arranged framework of the larger cluster. Reconstruction of these structural features via coarse-grained molecular simulations demonstrates that the cluster crystallization and the nanoscale phase separation between the two incompatible clusters synergistically result in the unique nano-architecture. Overall, this work opens up new opportunities for generating novel CAMs for advanced future applications.
RESUMO
Highly stretchable and super tough nanocomposite physical hydrogels (NCP gels) were fabricated by a facile and one-pot process. NCP gels show superior mechanical properties with tensile strength of 73 kPa-313 kPa and elongation at break of 1210-3420%. This is due to the effective strengthening mechanism: under stretching, the intermolecular hydrogen bonds can dynamically break and recombine to dissipate energy and homogenize the gel network. In addition, vinyl hybrid silica nanoparticles (VSNPs) can work as stress transfer centres to transfer stress to the grafted polymer chains.