• Researchers develop powerful strategy fo

    From ScienceDaily@1:317/3 to All on Mon May 2 22:30:40 2022
    Researchers develop powerful strategy for creating new-to-nature enzymes


    Date:
    May 2, 2022
    Source:
    University of Illinois at Urbana-Champaign Institute for
    Sustainability, Energy, and Environment
    Summary:
    Scientists achieve a novel biocatalytic reaction by repurposing
    natural enzymes with light, which could lead to valuable new
    chemical compounds.



    FULL STORY ========================================================================== Engineering enzymes to perform reactions not found in nature can address longstanding challenges in the world of synthetic chemistry, such as
    upgrading plant-based oils into useful biochemicals.


    ==========================================================================
    A team of researchers has developed a simple yet powerful strategy for
    creating new enzymes with novel reactivity that can produce valuable
    chemical compounds, building on their previous work using light to
    repurpose naturally occurring enzymes.

    The study, published in Nature Catalysis, was led by Xiaoqiang
    Huang, a former postdoctoral researcher in the University of Illinois Urbana-Champaign's Department of Chemical and Biomolecular Engineering
    (ChBE) and the Center for Advanced Bioenergy and Bioproducts Innovation (CABBI), a U.S. Department of Energy-funded Bioenergy Research
    Center. Huang, currently an Assistant Professor at the Nanjing University
    in China, carried out this work in the laboratory of ChBE Professor
    Huimin Zhao, CABBI's Conversion Theme Leader and an affiliate of the
    Carl R. Woese Institute for Genomic Biology (IGB).

    In the study, visible light was used to excite an engineered ketoreductase enzyme, enabling a new-to-nature biocatalytic reaction known as an
    asymmetric radical conjugate addition, which is extremely difficult to
    achieve by chemical catalysis.

    Catalysts are substances used to speed up chemical reactions. In living organisms, protein molecules called enzymes catalyze reactions in a
    process called biocatalysis. Scientists have begun using biocatalysis
    to synthesize valuable compounds, as its high selectivity allows them
    to deploy enzymes to act on specific substrates and create target
    products. Another advantage is that enzymatic reactions are highly
    sustainable. They are relatively inexpensive, consume low levels of
    energy, and do minimal damage to the environment -- as opposed to
    chemical catalysts, which typically require organic solvents, heat,
    and high pressure to function.

    Still, enzymes are complicated to work with. They are normally limited to catalyzing reactions found in nature, meaning scientists often struggle
    to track down the perfect biocatalyst to meet their needs. Zhao's lab
    has focused on steering biocatalysis with visible light, a process known
    as "photobiocatalysis," to produce new enzyme reactivity. In a previous
    study, Zhao and Huang developed a visible light-induced reaction using an enzyme named ene-reductase (ER) as a biocatalyst to produce high yields
    of valuable chiral carbonyl compounds, which have potential applications
    for production of high value chemicals.

    The new study builds on that work, using photobiocatalysis on a different enzyme family -- nicotamide-dependent ketoreductases produced by bacteria
    - - and a different chemical mechanism to produce another type of chiral carbonyl compounds known as a-chiral esters. Through the illumination
    and evolution of ketoreductase, the team achieved an enantioselective biocatalytic Giese-type radical conjugate addition to transform fatty
    acids to a-chiral esters, Zhao said.

    Enantioselectivity is the degree to which an enantiomer -- one of a pair
    of molecules that are mirror images of each other -- is preferentially
    produced in a chemical reaction. Chirality is a fundamental feature of
    organic compounds, which greatly influences the properties of molecules,
    and its implications are enormous in many areas, including biology,
    medicine, and material science. For example, the diverse stereochemistry
    of organic molecules (the spatial arrangement of atoms and its effect
    on chemical reactions) not only significantly enhances the richness of
    the biological world, but also plays a profound role in many biological activities such as molecular communication, he said.

    The findings offer practical applications for CABBI's work to develop
    biofuels and biochemicals from crops like miscanthus, sorghum, and
    energycane instead of petroleum. The new biocatalytic transformation could
    use the fatty acids that CABBI is generating from those plants as starting materials to synthesize value-added bioproducts -- such as ingredients
    for soaps or skin-care products -- in an environmentally friendly way.

    "Although we did not target a specific product for further application,
    this work provides a practical new method that could be potentially
    applied to upgrading fatty acids," Zhao said. "Enzymes are the workhorses
    for biological synthesis of fuels and chemicals from renewable biomass.

    "One of the major scientific changes in CABBI's Conversion research,
    or bioenergy research in general, is the lack of known enzymes with the
    desired activity and substrate specificity for the synthesis of target
    fuels and chemicals. Therefore, there is an urgent need to develop
    new strategies to discover or engineer enzymes with desired activity
    or reactivity." Co-authors on the study included CABBI Postdoctoral
    Fellow Guangde Jiang of ChBE; CABBI's Wesley Harrison, a Ph.D. candidate
    in ChBE and IGB; Jianqiang Feng and Binju Wang of Xiamen University,
    China; and Jiawen Cui, Xin Zang, and Jiahai Zhou of Shanghai Institute
    of Organic Chemistry, China. Zhou is also affiliated with the Chinese
    Academy of Sciences Shenzhen Institute of Advanced Technology, China.


    ========================================================================== Story Source: Materials provided by University_of_Illinois_at_Urbana-Champaign_Institute_for Sustainability,_Energy,_and_Environment. Note: Content may be edited
    for style and length.


    ========================================================================== Journal Reference:
    1. Xiaoqiang Huang, Jianqiang Feng, Jiawen Cui, Guangde Jiang, Wesley
    Harrison, Xin Zang, Jiahai Zhou, Binju Wang, Huimin
    Zhao. Photoinduced chemomimetic biocatalysis for enantioselective
    intermolecular radical conjugate addition. Nature Catalysis, 2022;
    DOI: 10.1038/s41929-022- 00777-4 ==========================================================================

    Link to news story: https://www.sciencedaily.com/releases/2022/05/220502170919.htm

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