5 research outputs found

    Cobalt-Catalyzed Asymmetric Addition of Silylacetylenes to 1,1-Disubstituted Allenes

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    The asymmetric addition of silylacetylenes to 1,1-disubstituted allenes proceeded in the presence of a cobalt/chiral bisphosphine ligand to give the corresponding enynes with high enantioselectivity. The results of deuterium-labeling experiments indicated that a hydrogen atom at the chiral center is originated from the terminal alkyne, and they were in good agreement with the proposed catalytic cycle where enantioselectivity is determined by the reaction of the proposed π-allylcobalt intermediate with the terminal alkyne

    Formation of Carbocycles via a 1,4-Rh Shift Triggered by a Rhodium-Catalyzed Addition of Terminal Alkynes to 3,3-Diarylcyclopropenes

    No full text
    The catalytic addition of terminal alkynes to 3,3-diarylcyclopropenes in the presence of a Rh­(I)/binap complex proceeded to give the cycloaddition products in good yields, where a 1,4-Rh shift is involved as a key step

    DNA Origami Based Visualization System for Studying Site-Specific Recombination Events

    No full text
    Site-specific recombination involves reciprocal exchange between defined DNA sites. The reaction initiates from the formation of a recombinase–DNA synaptic complex, in which two recombination sites arrange in an appropriate configuration. However, there is incomplete information about how the topological state of the substrate influences the synapsis and outcome of the reaction. Here, we show that Cre-mediated recombination can be regulated by controlling the orientation and topology of the <i>loxP</i> substrate in a DNA frame nanoscaffold. High-speed atomic force microscopy analyses revealed that the <i>loxP</i>-containing substrate strands in the antiparallel orientation can be recombined only through formation of synaptic complexes. By tethering Holliday junction (HJ) intermediates to DNA frames in different connection patterns and using them as a starting substrate, we found that the topological state of the HJ intermediates dictates the outcome of the resolution. Our approach should provide a new platform for structural–functional studies of various DNA targeting enzymes, especially which require formation of synaptic complexes

    DNA Origami Based Visualization System for Studying Site-Specific Recombination Events

    No full text
    Site-specific recombination involves reciprocal exchange between defined DNA sites. The reaction initiates from the formation of a recombinase–DNA synaptic complex, in which two recombination sites arrange in an appropriate configuration. However, there is incomplete information about how the topological state of the substrate influences the synapsis and outcome of the reaction. Here, we show that Cre-mediated recombination can be regulated by controlling the orientation and topology of the <i>loxP</i> substrate in a DNA frame nanoscaffold. High-speed atomic force microscopy analyses revealed that the <i>loxP</i>-containing substrate strands in the antiparallel orientation can be recombined only through formation of synaptic complexes. By tethering Holliday junction (HJ) intermediates to DNA frames in different connection patterns and using them as a starting substrate, we found that the topological state of the HJ intermediates dictates the outcome of the resolution. Our approach should provide a new platform for structural–functional studies of various DNA targeting enzymes, especially which require formation of synaptic complexes

    DNA Origami Based Visualization System for Studying Site-Specific Recombination Events

    No full text
    Site-specific recombination involves reciprocal exchange between defined DNA sites. The reaction initiates from the formation of a recombinase–DNA synaptic complex, in which two recombination sites arrange in an appropriate configuration. However, there is incomplete information about how the topological state of the substrate influences the synapsis and outcome of the reaction. Here, we show that Cre-mediated recombination can be regulated by controlling the orientation and topology of the <i>loxP</i> substrate in a DNA frame nanoscaffold. High-speed atomic force microscopy analyses revealed that the <i>loxP</i>-containing substrate strands in the antiparallel orientation can be recombined only through formation of synaptic complexes. By tethering Holliday junction (HJ) intermediates to DNA frames in different connection patterns and using them as a starting substrate, we found that the topological state of the HJ intermediates dictates the outcome of the resolution. Our approach should provide a new platform for structural–functional studies of various DNA targeting enzymes, especially which require formation of synaptic complexes
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