• Protein machinery of respiration becomes

    From ScienceDaily@1:317/3 to All on Mon Jan 31 21:30:44 2022
    Protein machinery of respiration becomes visible

    Date:
    January 31, 2022
    Source:
    University of Freiburg
    Summary:
    Researchers provide high-resolution electron microscopy analysis
    of the molecular machinery within the respiratory chain.



    FULL STORY ========================================================================== Researchers provide high-resolution electron microscopy analysis of the molecular machinery within the respiratory chain.


    ========================================================================== Oxygen and sugar are the basis of life for animals, plants, fungi
    and many bacteria. The metabolic process called respiration makes
    it possible to convert food into energy for the cells. Biochemist
    Prof. Dr. Carola Hunte and her team from the Cluster of Excellence CIBSS
    at the University of Freiburg have now visualized for the first time
    with unparalleled precision how an assembly of protein machines, which
    also supplies energy to humans, is structured and functions. The team
    studied two respiratory chain complexes fused into a supercomplex in a
    group of bacteria called Actinobacteria. In addition to providing a basic elucidation of respiratory processes, the cryogenic electron microscope analysis could aid in the development of new drugs to treat tuberculosis
    or diphtheria. "These images are like a journey into our molecular
    inner workings and its peculiar rules," Hunte explains, "Elucidating
    the structure simultaneously illuminates how the supercomplex works."
    The results of the study appeared in the journal Nature Communications
    and were produced in collaboration with Dr. Bruno Klaholz, research
    director at the Centre for Integrative Biology (CBI) / Institute of
    Genetics and of Molecular and Cellular Biology (IGBMC) of the CNRS,
    Inserm and the University of Strasbourg/France.

    The energy currency of the cell Adenosine triphosphate (ATP) is the energy currency of the cell -- the molecule is obtained during respiration and transfers energy from food to all processes in the cell. Thanks to the processes on the respiratory chain, adenosine diphosphate is turned into
    the energy-rich ATP. To do this, protein complexes of the respiratory
    chain build up an electrochemical driving force across a membrane with electrons and protons in a complicated chemical-physical process that
    is powered by the combustion of sugar.

    "We analyzed the respiratory cytochrome bcc-aa3 supercomplex. Twenty-six proteins make up the protein machine. The exact interaction of molecular
    forces and dynamics is not well understood yet, and this is where such
    a detailed description helps us," explains the study's first author
    Dr. Wei-Chun Kao of Hunte's team. The proton pump of the complex is very similar to humans, the researchers find, but the part where electrons
    are taken over by the electron carrier quinone shows clear differences in
    the bacterium. "This is where we could tie in and develop specific agents
    that kill pathogenic actinobacteria such as Mycobacterium tuberculosis or Corynebacterium diphtheriae by interfering with the respiratory chain,"
    Hunte adds.

    Cryogenic microscope with atomic resolution Cryogenic electron microscopy (Cryo-EM) is a technique that examines samples at low temperatures of --
    183 Celsius in a high-resolution microscope and can resolve structures to
    the level of single atoms. In the process, machine learning algorithms
    are used to further refine the collected data. "With this data, we
    can also better understand the interplay of metabolism and signalling,
    which is a particular focus in the Cluster of Excellence CIBSS," Hunte emphasizes. She is a member of the CIBSS speaker team, which develops integrative approaches to biological signalling research. The cryo-EM measurements took place at the CBI/IGBMC in Strasbourg/Illkirch. The
    Freiburg Research Collaboration Program from FRIAS -- Freiburg Institute
    of Advanced Studies supported this international collaboration.

    ========================================================================== Story Source: Materials provided by University_of_Freiburg. Note:
    Content may be edited for style and length.


    ========================================================================== Journal Reference:
    1. Wei-Chun Kao, Claire Ortmann de Percin Northumberland, Tat Cheung
    Cheng,
    Julio Ortiz, Alexandre Durand, Ottilie von Loeffelholz,
    Oliver Schilling, Martin L. Biniossek, Bruno P. Klaholz, Carola
    Hunte. Structural basis for safe and efficient energy conversion
    in a respiratory supercomplex.

    Nature Communications, 2022; 13 (1) DOI: 10.1038/s41467-022-28179-x ==========================================================================

    Link to news story: https://www.sciencedaily.com/releases/2022/01/220131153320.htm

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