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7 results on '"W. M. Keck Foundation"'

1. A seven-Earth-radius helium-burning star inside a 20.5-min detached binary

Author

National Natural Science Foundation of China, Ma Huateng Foundation, Beijing Association for Science and Technology, Natural Science Foundation of Yunnan Province, Czech Grant Agency, Ministero dell'Istruzione, dell'Università e della Ricerca, Istituto Nazionale di Astrofisica, Agencia Estatal de Investigación (España), Ministerio de Ciencia e Innovación (España), Ministerio de Ciencia, Innovación y Universidades (España), European Commission, National Aeronautics and Space Administration (US), W. M. Keck Foundation, National Science Foundation (US), Max Planck Institute for Astronomy, Gordon and Betty Moore Foundation, Lawrence Berkeley National Laboratory, European Space Agency, Lin, Jie, Wu, Chengyuan, Xiong, Heran, Wang, Xiaofeng, Elias-Rosa, Nancy, Salmaso, Irene, Filippenko, Alexei V., Brink, Thomas G., Yang, Yin, Li, Wenxiong, National Natural Science Foundation of China, Ma Huateng Foundation, Beijing Association for Science and Technology, Natural Science Foundation of Yunnan Province, Czech Grant Agency, Ministero dell'Istruzione, dell'Università e della Ricerca, Istituto Nazionale di Astrofisica, Agencia Estatal de Investigación (España), Ministerio de Ciencia e Innovación (España), Ministerio de Ciencia, Innovación y Universidades (España), European Commission, National Aeronautics and Space Administration (US), W. M. Keck Foundation, National Science Foundation (US), Max Planck Institute for Astronomy, Gordon and Betty Moore Foundation, Lawrence Berkeley National Laboratory, European Space Agency, Lin, Jie, Wu, Chengyuan, Xiong, Heran, Wang, Xiaofeng, Elias-Rosa, Nancy, Salmaso, Irene, Filippenko, Alexei V., Brink, Thomas G., Yang, Yin, and Li, Wenxiong

Abstract

Binary evolution theory predicts that the second common envelope ejection can produce low-mass (0.32–0.36 M⊙) subdwarf B (sdB) stars inside ultrashort-orbital-period binary systems, as their helium cores are ignited under nondegenerate conditions. With the orbital decay driven by gravitational-wave (GW) radiation, the minimum orbital periods of detached sdB binaries could be as short as ∼20 min. However, only four sdB binaries with orbital periods below an hour have been reported so far, and none of them has an orbital period approaching the above theoretical limit. Here we report the discovery of a 20.5-min-orbital-period ellipsoidal binary, TMTS J052610.43+593445.1, in which the visible star is being tidally deformed by an invisible carbon–oxygen white dwarf companion. The visible component is inferred to be an sdB star with a mass ∼0.33 M⊙ approaching the helium-ignition limit, although a He-core white dwarf cannot be completely ruled out. In particular, the radius of this low-mass sdB star is only 0.066 R⊙, about seven Earth radii. Such a system provides a key clue in mapping the binary evolution scheme from the second common envelope ejection to the formation of AM CVn stars having a helium-star donor. It may also serve as a crucial verification binary of space-borne GW observatories such as LISA and TianQin in the future.

Published
2024

2. Colloidal quasicrystals engineered with DNA

Author

Air Force Office of Scientific Research (US), Department of Energy (US), National Science Foundation (US), W. M. Keck Foundation, Ministerio de Ciencia, Innovación y Universidades (España), Agencia Estatal de Investigación (España), Ministerio de Ciencia e Innovación (España), Zhou, Wenjie, Lim, Yein, Lin, Haixin, Lee, Sangmin, Li, Yuanwei, Huang, Ziyin, Du, Jingshan S., Lee, Byeongdu, Wang, Shunzhi, Sánchez-Iglesias, Ana, Grzelczak, Marek, Liz-Marzán, Luis Manuel, Glotzer, Sharon C., Mirkin, Chad A., Air Force Office of Scientific Research (US), Department of Energy (US), National Science Foundation (US), W. M. Keck Foundation, Ministerio de Ciencia, Innovación y Universidades (España), Agencia Estatal de Investigación (España), Ministerio de Ciencia e Innovación (España), Zhou, Wenjie, Lim, Yein, Lin, Haixin, Lee, Sangmin, Li, Yuanwei, Huang, Ziyin, Du, Jingshan S., Lee, Byeongdu, Wang, Shunzhi, Sánchez-Iglesias, Ana, Grzelczak, Marek, Liz-Marzán, Luis Manuel, Glotzer, Sharon C., and Mirkin, Chad A.

Abstract

In principle, designing and synthesizing almost any class of colloidal crystal is possible. Nonetheless, the deliberate and rational formation of colloidal quasicrystals has been difficult to achieve. Here we describe the assembly of colloidal quasicrystals by exploiting the geometry of nanoscale decahedra and the programmable bonding characteristics of DNA immobilized on their facets. This process is enthalpy-driven, works over a range of particle sizes and DNA lengths, and is made possible by the energetic preference of the system to maximize DNA duplex formation and favour facet alignment, generating local five- and six-coordinated motifs. This class of axial structures is defined by a square-triangle tiling with rhombus defects and successive on-average quasiperiodic layers exhibiting stacking disorder which provides the entropy necessary for thermodynamic stability. Taken together, these results establish an engineering milestone in the deliberate design of programmable matter.

Published
2024

3. Shock cooling of a red-supergiant supernova at redshift 3 in lensed images

Author

Space Telescope Science Institute (US), University of Arizona, Smithsonian Institution, National Aeronautics and Space Administration (US), W. M. Keck Foundation, National Science Foundation (US), Agencia Estatal de Investigación (España), Japan Science and Technology Agency, Ministerio de Ciencia, Innovación y Universidades (España), Japan Society for the Promotion of Science, Ministry of Education, Culture, Sports, Science and Technology (Japan), United States-Israel Binational Science Foundation, Ministry of Science, Technology and Space (Israel), Berkeley Center for Cosmological Physics, European Commission, Chen, Wenlei, Kelly, Patrick L., Oguri, Masamune, Broadhurst, Tom, Diego, José María, Emami, Najmeh, Filippenko, Alexei V., Treu, Tommaso, Zitrin, Adi, Space Telescope Science Institute (US), University of Arizona, Smithsonian Institution, National Aeronautics and Space Administration (US), W. M. Keck Foundation, National Science Foundation (US), Agencia Estatal de Investigación (España), Japan Science and Technology Agency, Ministerio de Ciencia, Innovación y Universidades (España), Japan Society for the Promotion of Science, Ministry of Education, Culture, Sports, Science and Technology (Japan), United States-Israel Binational Science Foundation, Ministry of Science, Technology and Space (Israel), Berkeley Center for Cosmological Physics, European Commission, Chen, Wenlei, Kelly, Patrick L., Oguri, Masamune, Broadhurst, Tom, Diego, José María, Emami, Najmeh, Filippenko, Alexei V., Treu, Tommaso, and Zitrin, Adi

Abstract

The core-collapse supernova of a massive star rapidly brightens when a shock, produced following the collapse of its core, reaches the stellar surface. As the shock-heated star subsequently expands and cools, its early-time light curve should have a simple dependence on the size of the progenitor1 and therefore final evolutionary state. Measurements of the radius of the progenitor from early light curves exist for only a small sample of nearby supernovae2,3,4,5,6,7,8,9,10,11,12,13,14, and almost all lack constraining ultraviolet observations within a day of explosion. The several-day time delays and magnifying ability of galaxy-scale gravitational lenses, however, should provide a powerful tool for measuring the early light curves of distant supernovae, and thereby studying massive stellar populations at high redshift. Here we analyse individual rest-frame exposures in the ultraviolet to the optical taken with the Hubble Space Telescope, which simultaneously capture, in three separate gravitationally lensed images, the early phases of a supernova at redshift z ≈ 3 beginning within 5.8 ± 3.1 hours of explosion. The supernova, seen at a lookback time of approximately 11.5 billion years, is strongly lensed by an early-type galaxy in the Abell 370 cluster. We constrain the pre-explosion radius to be 533+154−119 solar radii, consistent with a red supergiant. Highly confined and massive circumstellar material at the same radius can also reproduce the light curve, but because no similar low-redshift examples are known, this is unlikely.

Published
2022

4. MEMOTE for standardized genome-scale metabolic model testing

Author

Research Council of Norway, Innovation Fund Denmark, European Commission, National Institutes of Health (US), German Research Foundation, Novo Nordisk Foundation, W. M. Keck Foundation, Ministerio de Economía y Competitividad (España), Knut and Alice Wallenberg Foundation, Federal Ministry of Education and Research (Germany), Bill & Melinda Gates Foundation, National Research Foundation of Korea, Rural Development Administration (South Korea), Swiss National Science Foundation, University of Oxford, European Research Council, Washington Research Foundation, National Institute of General Medical Sciences (US), Lieven, Christian, Beber, Moritz E., Olivier, Brett G., Bergmann, Frank T., Ataman, Meric, Babaei, Parizad, Bartell, Jennifer A., Blank, Lars M., Chauhan, Siddharth, Correia, Kevin, Diener, Christian, Dräger, Andreas, Ebert, Birgitta E., Edirisinghe, Janaka N., Faria, José P., Feist, Adam M., Fengos, Georgios, Fleming, Ronan M. T., García-Jiménez, Beatriz, Hatzimanikatis, Vassily, Van Helvoirt, Wout, Henry, Christopher S., Hermjakob, Henning, Herrgård, Markus J., Kaafarani, Ali, Kim, Hyun Uk, King, Zachary, Klamt, Steffen, Klipp, Edda, Koehorst, Jasper J., König, Matthias, Lakshmanan, Meiyappan, Lee, Dong-Yup, Lee, Sang Yup, Lee, Sunjae, Lewis, Nathan E., Liu, Filipe, Ma, Hongwu, Machado, Daniel, Mahadevan, Radhakrishnan, Maia, Paulo, Mardinoglu, Adil, Medlock, Gregory L., Monk, Jonathan M., Nielsen, Jens, Nielsen, Lars K., Nogales, Juan, Nookaew, Intawat, Palsson, Bernhard Ø, Papin, Jason A., Patil, Kiran R., Poolman, Mark, Price, Nathan D., Resendis-Antonio, Osbaldo, Richelle, Anne, Rocha, Isabel, Sánchez, Benjamín J., Schaap, Peter J., Malik Sheriff, Rahuman S., Shoaie, Saeed, Sonnenschein, Nikolaus, Teusink, Bas, Vilaça, Paulo, Vik, Jon Olav, Wodke, Judith A. H., Xavier, Joana C., Yuan, Qianqian, Zakhartsev, Maksim, Zhang, Cheng, Research Council of Norway, Innovation Fund Denmark, European Commission, National Institutes of Health (US), German Research Foundation, Novo Nordisk Foundation, W. M. Keck Foundation, Ministerio de Economía y Competitividad (España), Knut and Alice Wallenberg Foundation, Federal Ministry of Education and Research (Germany), Bill & Melinda Gates Foundation, National Research Foundation of Korea, Rural Development Administration (South Korea), Swiss National Science Foundation, University of Oxford, European Research Council, Washington Research Foundation, National Institute of General Medical Sciences (US), Lieven, Christian, Beber, Moritz E., Olivier, Brett G., Bergmann, Frank T., Ataman, Meric, Babaei, Parizad, Bartell, Jennifer A., Blank, Lars M., Chauhan, Siddharth, Correia, Kevin, Diener, Christian, Dräger, Andreas, Ebert, Birgitta E., Edirisinghe, Janaka N., Faria, José P., Feist, Adam M., Fengos, Georgios, Fleming, Ronan M. T., García-Jiménez, Beatriz, Hatzimanikatis, Vassily, Van Helvoirt, Wout, Henry, Christopher S., Hermjakob, Henning, Herrgård, Markus J., Kaafarani, Ali, Kim, Hyun Uk, King, Zachary, Klamt, Steffen, Klipp, Edda, Koehorst, Jasper J., König, Matthias, Lakshmanan, Meiyappan, Lee, Dong-Yup, Lee, Sang Yup, Lee, Sunjae, Lewis, Nathan E., Liu, Filipe, Ma, Hongwu, Machado, Daniel, Mahadevan, Radhakrishnan, Maia, Paulo, Mardinoglu, Adil, Medlock, Gregory L., Monk, Jonathan M., Nielsen, Jens, Nielsen, Lars K., Nogales, Juan, Nookaew, Intawat, Palsson, Bernhard Ø, Papin, Jason A., Patil, Kiran R., Poolman, Mark, Price, Nathan D., Resendis-Antonio, Osbaldo, Richelle, Anne, Rocha, Isabel, Sánchez, Benjamín J., Schaap, Peter J., Malik Sheriff, Rahuman S., Shoaie, Saeed, Sonnenschein, Nikolaus, Teusink, Bas, Vilaça, Paulo, Vik, Jon Olav, Wodke, Judith A. H., Xavier, Joana C., Yuan, Qianqian, Zakhartsev, Maksim, and Zhang, Cheng

Abstract

Reconstructing metabolic reaction networks enables the development of testable hypotheses of an organism’s metabolism under different conditions1. State-of-the-art genome-scale metabolic models (GEMs) can include thousands of metabolites and reactions that are assigned to subcellular locations. Gene–protein–reaction (GPR) rules and annotations using database information can add meta-information to GEMs. GEMs with metadata can be built using standard reconstruction protocols2, and guidelines have been put in place for tracking provenance and enabling interoperability, but a standardized means of quality control for GEMs is lacking3. Here we report a community effort to develop a test suite named MEMOTE (for metabolic model tests) to assess GEM quality.

Published
2020

5. Eukaryotic transcription factors can track and control their target genes using DNA antennas

Author

European Research Council, Ministerio de Economía y Competitividad (España), W. M. Keck Foundation, National Science Foundation (US), Castellanos, Milagros, Mothi, Nivin, Muñoz, Víctor, European Research Council, Ministerio de Economía y Competitividad (España), W. M. Keck Foundation, National Science Foundation (US), Castellanos, Milagros, Mothi, Nivin, and Muñoz, Víctor

Abstract

Eukaryotic transcription factors (TF) function by binding to short 6-10 bp DNA recognition sites located near their target genes, which are scattered through vast genomes. Such process surmounts enormous specificity, efficiency and celerity challenges using a molecular mechanism that remains poorly understood. Combining biophysical experiments, theory and bioinformatics, we dissect the interplay between the DNA-binding domain of Engrailed, a Drosophila TF, and the regulatory regions of its target genes. We find that Engrailed binding affinity is strongly amplified by the DNA regions flanking the recognition site, which contain long tracts of degenerate recognition-site repeats. Such DNA organization operates as an antenna that attracts TF molecules in a promiscuous exchange among myriads of intermediate affinity binding sites. The antenna ensures a local TF supply, enables gene tracking and fine control of the target site’s basal occupancy. This mechanism illuminates puzzling gene expression data and suggests novel engineering strategies to control gene expression.

Published
2020

6. Design of Protein Assemblies with Built-In Allosteric Control Based on Monomer Fold-Switching

Author

European Research Council, Ministerio de Economía y Competitividad (España), W. M. Keck Foundation, ALBA Synchrotron, Campos, Luis A., Sharma, Rajendra, Alvira, Sara, Ruiz, Federico M., Ibarra-Molero, Beatriz, Sadqi, Mourad, Alfonso, Carlos, Rivas, Germán, Sánchez-Ruiz, José M., Romero, Antonio, Valpuesta, José M., Muñoz, Víctor, European Research Council, Ministerio de Economía y Competitividad (España), W. M. Keck Foundation, ALBA Synchrotron, Campos, Luis A., Sharma, Rajendra, Alvira, Sara, Ruiz, Federico M., Ibarra-Molero, Beatriz, Sadqi, Mourad, Alfonso, Carlos, Rivas, Germán, Sánchez-Ruiz, José M., Romero, Antonio, Valpuesta, José M., and Muñoz, Víctor

Abstract

The macromolecular machines of life use allosteric control to self-assemble, dissociate and change shape in response to signals. Despite enormous interest, the design of nanoscale allosteric assemblies has proven tremendously challenging. Here we present a proof of concept of allosteric assembly in which an engineered fold switch on the protein monomer triggers or blocks assembly. Our design is based on the hyper-stable, naturally monomeric protein CI2, a paradigm of simple two-state folding, and the toroidal arrangement with 6-fold symmetry that it only adopts in crystalline form. We engineer CI2 to enable a switch between the native and an alternate, latent fold that self-assembles onto hexagonal toroidal particles by exposing a favorable inter-monomer interface. The assembly is controlled on demand via the competing effects of temperature and a designed short peptide. These findings unveil a remarkable potential for structural metamorphosis in proteins and demonstrate key principles for engineering protein-based nanomachinery.

Published
2019

7. Design of Protein Assemblies with Built-In Allosteric Control Based on Monomer Fold-Switching

Author

Campos, Luis A., Sharma, Rajendra, Alvira, Sara, Ruiz, Federico M., Ibarra-Molero, Beatriz, Sadqi, Mourad, Alfonso, Carlos, Rivas, Germán, Sánchez-Ruiz, José M., Romero, Antonio, Valpuesta, José M., Muñoz, Víctor, European Research Council, Ministerio de Economía y Competitividad (España), W. M. Keck Foundation, and ALBA Synchrotron

Subjects
Computational biophysics, Molecular engineering, Nanobiotechnology, Protein folding, Structural biology
Abstract

© The Author(s) 2019., The macromolecular machines of life use allosteric control to self-assemble, dissociate and change shape in response to signals. Despite enormous interest, the design of nanoscale allosteric assemblies has proven tremendously challenging. Here we present a proof of concept of allosteric assembly in which an engineered fold switch on the protein monomer triggers or blocks assembly. Our design is based on the hyper-stable, naturally monomeric protein CI2, a paradigm of simple two-state folding, and the toroidal arrangement with 6-fold symmetry that it only adopts in crystalline form. We engineer CI2 to enable a switch between the native and an alternate, latent fold that self-assembles onto hexagonal toroidal particles by exposing a favorable inter-monomer interface. The assembly is controlled on demand via the competing effects of temperature and a designed short peptide. These findings unveil a remarkable potential for structural metamorphosis in proteins and demonstrate key principles for engineering protein-based nanomachinery., This work was supported by the European Research Council (grant ERC-2012-ADG-323059 to V.M.) and by the PRODESTECH network funded through the CONSOLIDER program from the Spanish Government (grant CSD2009-00088). L.A.C. acknowledges support from Ministry of Economy and Competitiveness through grants BIO2016-78768-P and RYC-2013-13197. V.M. acknowledges additional support from the W.M. Keck Foundation and from the CREST Center for Cellular and Biomomolecular Machines (grant NSF-CREST-1547848). J.M.V. acknowledges additional support from Ministry of Economy and Competitiveness through grant BFU2016-75984. F.M.R. and A.R. thank the staff from the ALBA synchrotron (Spain) for assistance with the XALOC beamline. Structural data are deposited in the Protein Data Bank with accession codes 6QIY (X-ray CI2 classical geometry) and 6QIZ (X-ray CI2 domain swapped) and EMD-4568 (cryo-EM CI2eng assembly).

Published
2019

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