Related Experiment Video

Updated: Feb 7, 2026

Measurement of Heme Synthesis Levels in Mammalian Cells
09:43

Measurement of Heme Synthesis Levels in Mammalian Cells

Published on: July 9, 2015

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Moraxella catarrhalis HemW is a Heme-binding Radical SAM Enzyme

Caitlin M Padgett, Melissa M Bollmeyer, Kaleb Boswinkle

    Biorxiv : the Preprint Server for Biology
    |February 6, 2026
    PubMed

    Insights

    Moraxella catarrhalis growth requires the HemW protein, which binds heme. This discovery offers a new strategy for targeting iron metabolism in this important respiratory pathogen.

    Area of Science:

    • Microbiology
    • Biochemistry
    • Pathogen Research

    Background:

    • Moraxella catarrhalis is a key respiratory pathogen causing otitis media and COPD exacerbations.
    • Iron acquisition is crucial for bacterial survival, and pathogens face host-imposed nutritional immunity.
    • The function of the essential gene hemW in M. catarrhalis remained uncharacterized.

    Purpose of the Study:

    • To biochemically characterize the essential HemW protein from Moraxella catarrhalis.
    • To investigate the role of HemW in bacterial growth under iron-limiting conditions.
    • To explore HemW as a potential therapeutic target.

    Main Methods:

    • Bioinformatic analysis to establish evolutionary relationships.
    • Biochemical assays to determine enzymatic activity.
    • Spectroscopic methods to analyze cofactor binding.

    Main Results:

    • Mc HemW shares homology with radical S-adenosylmethionine enzymes, specifically heme-binding ones.
    • Mc HemW possesses a catalytically active [4Fe-4S] cluster.
    • Mc HemW demonstrates heme-binding capability in vitro.

    Conclusions:

    • Mc HemW functions as a putative heme chaperone in Moraxella catarrhalis.
    • HemW's role in heme binding and iron metabolism makes it a promising target for novel antimicrobial strategies.
    • Understanding HemW is vital for developing new treatments against M. catarrhalis infections.

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