Silkworm silks have been widely used in a variety of fields due to their sensuousness, luster and excellent mechanical properties. Researchers have paid special attention in improving the mechanical properties of silk...Silkworm silks have been widely used in a variety of fields due to their sensuousness, luster and excellent mechanical properties. Researchers have paid special attention in improving the mechanical properties of silks. In this work,Bombyx mori larval silkworms are injected with graphene quantum dots(GQDs) through a vascular injection to enhance mechanical properties of the silkworm silks. The GQDs can be incorporated into the silkworm silk gland easily due to hemolymph circulation and influence the spinning process of silkworm. The breaking strength, elongation at break and toughness modulus of the silks increase by 2.74, 1.33 and 3.62 times, respectively, by injecting per individual with 0.6 μg GQDs. Wide-angle X-ray scattering indicates that the size ofβ-sheet nanocrystals in GQDs-silks is smaller than that in control-silks. Infrared spectra suggest that GQDs confine the conformation transition of silk fibroin to β-sheet from random coil/α-helix, and the change of the size and content of β-sheet may be the reason for the improvement of the mechanical properties. The toxicity and safety limit of GQDs incorporated into each silkworm is also evaluated, and the results show that the upmost dose of GQDs per silkworm is30.0 μg. The successful obtainment of reinforced silks by in vivo uptake of GQDs provides a promising route to produce high-strength silks.展开更多
Recent studies have demonstrated that the membrane-proximal external region （MPER） of human immunodeficiency virus 1 （HIV-1） glycoprotein 41 contains a series of epitopes for human monoclonal antibodies, including...Recent studies have demonstrated that the membrane-proximal external region （MPER） of human immunodeficiency virus 1 （HIV-1） glycoprotein 41 contains a series of epitopes for human monoclonal antibodies, including 2F5, Zl3el, 4El0, and 10E8, which were isolated from HIV-l-infected individuals and show broad neutralizing activities. This suggests that MPER is a good target for the development of effective HIV-1 vaccines. However, many studies have shown that it is difficult to induce antibodies with similar broad neutralizing activities using MPER-based peptide antigens. Here, we report that 10E8-1ike neu- tralizing antibodies with effective anti-HIV-1 activity were readily induced using a precisely designed conformational immu- nogenic peptide containing the 10E8-specific epitope. This immunogenic peptide （designated T10HE） contains a 15-mer MPER-derived 10E8-specific epitope fused to T-helper-cell epitopes from tetanus toxin （tt）, which showed a significantly sta- bilized a-helix structure after a series of modifications, including substitution with an （S）-c^-（2＇-pentenyl） alanine containing an olefin-bearing tether and ruthenium-catalyzed olefin metathesis, compared with the unmodified T10E peptide. The stabilized （x-helix structure of T10HE did not affect its capacity to bind the 10E8 antibody, as evaluated with an enzyme linked immuno- sorbent assay （ELISA） and surface plasmon resonance binding assay （SPR assay）. The efficacies of the T10HE and T10E epitope vaccines were evaluated after a standard vaccination procedure in which the experimental mice were primed with ei- ther the T10HE or T10E immunogen and boosted with HIV-1 JRFL pseudoviruses. Higher titers of 10E8-1ike antibodies were induced by T10HE than that by T10E. More importantly, the antibodies induced by T10HE showed enhanced antiviral potency against HIV-1 strains with both X4 and R5 tropism and a greater degree of broad neutralizing activity than the antibodies in- duced by T10E. These results indicate that a 10E8-epitope-based structure-specific peptide immunogen can elicit neutralizing antibodies when used as a vaccine prime.展开更多
To understand how the stabilities of key nuclei fragments affect protein folding dynamics, we simulate by molecular dynamics （MD） simulation in aqueous solution four fragments cut out of a protein G, including one a...To understand how the stabilities of key nuclei fragments affect protein folding dynamics, we simulate by molecular dynamics （MD） simulation in aqueous solution four fragments cut out of a protein G, including one a-helix （seqB： KVFKQYAN）, two -turns （seqA： LNGKTLKG and seqC： YDDATKTF）, and one -strand （seqD： DGEWTYDD）. The Markov State Model clustering method combined with the coarse-grained conformation letters method are employed to analyze the data sampled from 2-#s equilibrium MD simulation trajectories. We find that seqA and seqB have more stable structures than their native structures which become metastable when cut out of the protein structure. As expected, seqD alone is flexible and does not have a stable structure. Throughout our simulations, the native structure of seqC is stable but cannot be reached if starting from a structure other than the native one, implying a funnel-shape free energy landscape of seqC in aqueous solution. All the above results suggest that different nuclei have different formation dynamics during protein folding, which may have a major contribution to the hierarchy of protein folding dynamics.展开更多
基金supported by the Young Elite Scientist Sponsorship Program by CAST (2015QNRC001)the Earmarked Fund for Modern Agro-industry Technology Research System
文摘Silkworm silks have been widely used in a variety of fields due to their sensuousness, luster and excellent mechanical properties. Researchers have paid special attention in improving the mechanical properties of silks. In this work,Bombyx mori larval silkworms are injected with graphene quantum dots(GQDs) through a vascular injection to enhance mechanical properties of the silkworm silks. The GQDs can be incorporated into the silkworm silk gland easily due to hemolymph circulation and influence the spinning process of silkworm. The breaking strength, elongation at break and toughness modulus of the silks increase by 2.74, 1.33 and 3.62 times, respectively, by injecting per individual with 0.6 μg GQDs. Wide-angle X-ray scattering indicates that the size ofβ-sheet nanocrystals in GQDs-silks is smaller than that in control-silks. Infrared spectra suggest that GQDs confine the conformation transition of silk fibroin to β-sheet from random coil/α-helix, and the change of the size and content of β-sheet may be the reason for the improvement of the mechanical properties. The toxicity and safety limit of GQDs incorporated into each silkworm is also evaluated, and the results show that the upmost dose of GQDs per silkworm is30.0 μg. The successful obtainment of reinforced silks by in vivo uptake of GQDs provides a promising route to produce high-strength silks.
基金supported by Ministry of Science and Technology of China(2012ZX10001-009)
文摘Recent studies have demonstrated that the membrane-proximal external region （MPER） of human immunodeficiency virus 1 （HIV-1） glycoprotein 41 contains a series of epitopes for human monoclonal antibodies, including 2F5, Zl3el, 4El0, and 10E8, which were isolated from HIV-l-infected individuals and show broad neutralizing activities. This suggests that MPER is a good target for the development of effective HIV-1 vaccines. However, many studies have shown that it is difficult to induce antibodies with similar broad neutralizing activities using MPER-based peptide antigens. Here, we report that 10E8-1ike neu- tralizing antibodies with effective anti-HIV-1 activity were readily induced using a precisely designed conformational immu- nogenic peptide containing the 10E8-specific epitope. This immunogenic peptide （designated T10HE） contains a 15-mer MPER-derived 10E8-specific epitope fused to T-helper-cell epitopes from tetanus toxin （tt）, which showed a significantly sta- bilized a-helix structure after a series of modifications, including substitution with an （S）-c^-（2＇-pentenyl） alanine containing an olefin-bearing tether and ruthenium-catalyzed olefin metathesis, compared with the unmodified T10E peptide. The stabilized （x-helix structure of T10HE did not affect its capacity to bind the 10E8 antibody, as evaluated with an enzyme linked immuno- sorbent assay （ELISA） and surface plasmon resonance binding assay （SPR assay）. The efficacies of the T10HE and T10E epitope vaccines were evaluated after a standard vaccination procedure in which the experimental mice were primed with ei- ther the T10HE or T10E immunogen and boosted with HIV-1 JRFL pseudoviruses. Higher titers of 10E8-1ike antibodies were induced by T10HE than that by T10E. More importantly, the antibodies induced by T10HE showed enhanced antiviral potency against HIV-1 strains with both X4 and R5 tropism and a greater degree of broad neutralizing activity than the antibodies in- duced by T10E. These results indicate that a 10E8-epitope-based structure-specific peptide immunogen can elicit neutralizing antibodies when used as a vaccine prime.
基金Supported by the National Basic Research Program of China under Grant No.2013CB932804the National Natural Science Foundation of China under Grant No.11421063the CAS Biophysics Interdisciplinary Innovation Team Project
文摘To understand how the stabilities of key nuclei fragments affect protein folding dynamics, we simulate by molecular dynamics （MD） simulation in aqueous solution four fragments cut out of a protein G, including one a-helix （seqB： KVFKQYAN）, two -turns （seqA： LNGKTLKG and seqC： YDDATKTF）, and one -strand （seqD： DGEWTYDD）. The Markov State Model clustering method combined with the coarse-grained conformation letters method are employed to analyze the data sampled from 2-#s equilibrium MD simulation trajectories. We find that seqA and seqB have more stable structures than their native structures which become metastable when cut out of the protein structure. As expected, seqD alone is flexible and does not have a stable structure. Throughout our simulations, the native structure of seqC is stable but cannot be reached if starting from a structure other than the native one, implying a funnel-shape free energy landscape of seqC in aqueous solution. All the above results suggest that different nuclei have different formation dynamics during protein folding, which may have a major contribution to the hierarchy of protein folding dynamics.
