Catálogo de publicaciones - revistas

<jats:title>Wavy walls built by nanofilaments</jats:title> <jats:p> In the model plant <jats:italic>Arabidopsis</jats:italic> , pavement cells fit together with the lobes and curves of jigsaw puzzle pieces. Such complex cell shapes, in plants, were generally thought to be driven by turgor pressure. Haas <jats:italic>et al.</jats:italic> now show that the extracellular cell wall can actively shape the cell it contains without relying on turgor pressure. Nanofilaments of pectin homogalacturonan in the cell wall shift between crystalline and anisotropic phases according to whether they are methylated. The shift in form drives changes in cell wall shape that stand independent of turgor pressure. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6481" page="1003" related-article-type="in-this-issue" vol="367" xlink:href="10.1126/science.aaz5103">1003</jats:related-article> </jats:p>

<jats:title>Hefty structures of IgA and IgM complexes</jats:title> <jats:p> Immunoglobulin M (IgM) and IgA are antibody isotypes that can form higher-order secretory complexes (sIgM and sIgA), which allows them to effectively bind and neutralize antigens with low-affinity repetitive epitopes, such as those found on the surface of many bacteria and viruses. The assembly and transport of these molecules is also dependent on the joining chain (J-chain) and the polymeric immunoglobulin receptor (pIgR) secretory component (SC). The architecture of these complex, multimeric structures has remained elusive. Li <jats:italic>et al.</jats:italic> resolved cryo–electron microscopy structures of the sIgM-Fc pentamer in complex with the J-chain and SC. Using similar techniques, Kumar <jats:italic>et al.</jats:italic> visualized dimeric, tetrameric, and pentameric structures of secretory sIgA-Fc interacting with the J-chain and SC. Both groups report highly similar mechanisms wherein the J-chain serves as a template for antibody oligomerization. An unanticipated, amyloid-like assembly of the oligomerized structure is present in both cases, with the J-chain conferring asymmetry for pIgR binding and transcytosis. These studies may inform structure-based engineering of these molecules for future therapeutic purposes. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6481" page="1014" related-article-type="in-this-issue" vol="367" xlink:href="10.1126/science.aaz5425">1014</jats:related-article> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6481" page="1008" related-article-type="in-this-issue" vol="367" xlink:href="10.1126/science.aaz5807">1008</jats:related-article> </jats:p>

<jats:title>Hefty structures of IgA and IgM complexes</jats:title> <jats:p> Immunoglobulin M (IgM) and IgA are antibody isotypes that can form higher-order secretory complexes (sIgM and sIgA), which allows them to effectively bind and neutralize antigens with low-affinity repetitive epitopes, such as those found on the surface of many bacteria and viruses. The assembly and transport of these molecules is also dependent on the joining chain (J-chain) and the polymeric immunoglobulin receptor (pIgR) secretory component (SC). The architecture of these complex, multimeric structures has remained elusive. Li <jats:italic>et al.</jats:italic> resolved cryo–electron microscopy structures of the sIgM-Fc pentamer in complex with the J-chain and SC. Using similar techniques, Kumar <jats:italic>et al.</jats:italic> visualized dimeric, tetrameric, and pentameric structures of secretory sIgA-Fc interacting with the J-chain and SC. Both groups report highly similar mechanisms wherein the J-chain serves as a template for antibody oligomerization. An unanticipated, amyloid-like assembly of the oligomerized structure is present in both cases, with the J-chain conferring asymmetry for pIgR binding and transcytosis. These studies may inform structure-based engineering of these molecules for future therapeutic purposes. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6481" page="1014" related-article-type="in-this-issue" vol="367" xlink:href="10.1126/science.aaz5425">1014</jats:related-article> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6481" page="1008" related-article-type="in-this-issue" vol="367" xlink:href="10.1126/science.aaz5807">1008</jats:related-article> </jats:p>

<jats:title>Ultrafast vortex microlasers</jats:title> <jats:p> For applications in ultrafast communication, all-optical switches will require low energy consumption, high speed, a strong modulation ratio, a small footprint, and on-chip integration. Although the small footprint and on-chip integration are accessible, the trade-off between low energy consumption and high speed has been challenging. Huang <jats:italic>et al.</jats:italic> exploited the idea of bound states in the continuum, effectively a high–quality ( <jats:italic>Q</jats:italic> ) cavity without the physical cavity, to design vortex lasers with highly directional output and single-mode operation. With the trade-off between low energy consumption and high speed now broken, it should be possible to realize ultrafast optical switching that meets all the requirements of modern classic and quantum information. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6481" page="1018" related-article-type="in-this-issue" vol="367" xlink:href="10.1126/science.aba4597">1018</jats:related-article> </jats:p>

<jats:title>Amines as a gateway to alkyl radicals</jats:title> <jats:p> In recent years, photoredox catalysis driven by blue light has often been used to oxidize carbon centers adjacent to nitrogen. Constantin <jats:italic>et al.</jats:italic> now show that these aminoalkyl radicals can, in turn, conveniently strip iodine atoms from a variety of alkyl carbons. The new alkyl radicals that result readily undergo deuteration and couplings such as alkylation, allylation, and olefination. The upshot is that simple amines can replace more hazardous conventional reagents such as trialkyltin compounds in the homolytic activation and functionalization of halocarbons. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6481" page="1021" related-article-type="in-this-issue" vol="367" xlink:href="10.1126/science.aba2419">1021</jats:related-article> </jats:p>