Plasmonic Ag nanowire homotrimer with asymmetrical radii and separations, which exhibits characteristics of multiple plamonic resonances and different electric field distributions, is systematically investigated by me...Plasmonic Ag nanowire homotrimer with asymmetrical radii and separations, which exhibits characteristics of multiple plamonic resonances and different electric field distributions, is systematically investigated by means of 2D finite element method. It was found that the dark and bright modes appear in asymmetrical nanowire homotrimer. In addition, when the dark modes appear between the smaller radii of the nanowires, the cascade effect results in enhanced electric field between the smaller radii nanowires. As a result of the appearance of the bright modes between the smaller radii of the nanowires, the restriction of the cascade effect generates enhanced electric field between the bigger nanowires.展开更多
The decapentaplegic(Dpp),a member of the TGF-β superfamily,plays a pivotal role in the control of proliferation,global patterning and induction of specific cell fates during Drosophila development.Mother against Dpp(...The decapentaplegic(Dpp),a member of the TGF-β superfamily,plays a pivotal role in the control of proliferation,global patterning and induction of specific cell fates during Drosophila development.Mother against Dpp(Mad) is the founding member of the conserved Smad protein family which spe-cifically transduces the intracellular TGF-β signaling cascade.Here we report the 2.80 structure of the MH2 domain of Mad(Mad-MH2) that was readily superposed to the mammal Smad-MH2 structures.This unphosphorylated Mad-MH2 forms a symmetric homotrimer in crystals,consistent with the result of the size-exclusion chromatography that Mad-MH2 exhibited a propensity for concentration-dependent oligomerization prior to phosphorylation.Structural analysis revealed that the formation of homotrimeric Mad-MH2 is mainly mediated by contacts involving the extreme C-terminal SSVS motif,and is strengthened by phosphorylation of the last two Ser residues which was confirmed by the gel filtration analysis of the pseudophosphorylated Mad-MH2(DVD).Intriguingly,the homotrimer within an asymmetric unit only possesses two ordered C-terminal tails,reminiscent of the arrangement of the R-Smad/Smad4 complexes,indicating that the subunit with a flexible SSXS motif would be readily replaced by Co-Smad to form a functional heterotrimer.展开更多
文摘Plasmonic Ag nanowire homotrimer with asymmetrical radii and separations, which exhibits characteristics of multiple plamonic resonances and different electric field distributions, is systematically investigated by means of 2D finite element method. It was found that the dark and bright modes appear in asymmetrical nanowire homotrimer. In addition, when the dark modes appear between the smaller radii of the nanowires, the cascade effect results in enhanced electric field between the smaller radii nanowires. As a result of the appearance of the bright modes between the smaller radii of the nanowires, the restriction of the cascade effect generates enhanced electric field between the bigger nanowires.
基金Supported by National Key Basic Research and Development Program of China (Grant Nos. 2006CB503900 and 2007CB914400)China National Funds for Distinguished Young Scientists (Grant No. 30425005)
文摘The decapentaplegic(Dpp),a member of the TGF-β superfamily,plays a pivotal role in the control of proliferation,global patterning and induction of specific cell fates during Drosophila development.Mother against Dpp(Mad) is the founding member of the conserved Smad protein family which spe-cifically transduces the intracellular TGF-β signaling cascade.Here we report the 2.80 structure of the MH2 domain of Mad(Mad-MH2) that was readily superposed to the mammal Smad-MH2 structures.This unphosphorylated Mad-MH2 forms a symmetric homotrimer in crystals,consistent with the result of the size-exclusion chromatography that Mad-MH2 exhibited a propensity for concentration-dependent oligomerization prior to phosphorylation.Structural analysis revealed that the formation of homotrimeric Mad-MH2 is mainly mediated by contacts involving the extreme C-terminal SSVS motif,and is strengthened by phosphorylation of the last two Ser residues which was confirmed by the gel filtration analysis of the pseudophosphorylated Mad-MH2(DVD).Intriguingly,the homotrimer within an asymmetric unit only possesses two ordered C-terminal tails,reminiscent of the arrangement of the R-Smad/Smad4 complexes,indicating that the subunit with a flexible SSXS motif would be readily replaced by Co-Smad to form a functional heterotrimer.
