Dissertation
Breathing in Thin Air: Structure, Function and Therapeutic Opportunities of bd-type Oxidases
The increasing prevalence of antibiotic resistance has created an urgent need for new therapeutic strategies against bacterial pathogens such as Mycobacterium tuberculosis.
- Author
- T.T. van der Velden
- Date
- 02 September 2026
- Links
- Thesis in Leiden Repository
The bacterial respiratory chain has emerged as a promising target for antimicrobial development, with the terminal oxidase cytochrome bd playing a key role in bacterial survival during low oxygen conditions and oxidative stress. This thesis investigates the molecular mechanism, regulation, and therapeutic potential of cytochrome bd using structural, biochemical, and drug discovery approaches. We show that M. tuberculosis cytochrome bd is a menaquinone-specific oxidase whose activity is regulated by a unique redox-sensitive disulfide bond within the substrate-binding Q-loop, revealing a potential mechanism for rapid adaptation to oxidative stress. Cryo-electron microscopy of E. coli cytochrome bd provides the first structural insights into quinone turnover and competitive inhibition, defining the molecular basis of substrate recognition. Building on these findings, a rapid screening strategy identified a novel inhibitor scaffold targeting the quinone-binding site with sub-micromolar potency. Finally, evidence is presented for a direct interaction between the heme transporter CydDC and the catalytic subunit CydA, suggesting an alternative mechanism for cytochrome bd maturation. Together, these findings advance our understanding of bacterial respiration and provide a foundation for the development of cytochrome bd-targeted antibiotics against tuberculosis and other persistent bacterial infections.