In silico investigation of cytochrome bc1 molecular inhibition mechanism against Trypanosoma cruzi

PLoS Negl Trop Dis. 2023 Jan 23;17(1):e0010545. doi: 10.1371/journal.pntd.0010545. eCollection 2023 Jan.

Abstract

Chagas' disease is a neglected tropical disease caused by the kinetoplastid protozoan Trypanosoma cruzi. The only therapies are the nitroheterocyclic chemicals nifurtimox and benznidazole that cause various adverse effects. The need to create safe and effective medications to improve medical care remains critical. The lack of verified T. cruzi therapeutic targets hinders medication research for Chagas' disease. In this respect, cytochrome bc1 has been identified as a promising therapeutic target candidate for antibacterial medicines of medical and agricultural interest. Cytochrome bc1 belongs to the mitochondrial electron transport chain and transfers electrons from ubiquinol to cytochrome c1 by the action of two catalytic sites named Qi and Qo. The two binding sites are highly selective, and specific inhibitors exist for each site. Recent studies identified the Qi site of the cytochrome bc1 as a promising drug target against T. cruzi. However, a lack of knowledge of the drug mechanism of action unfortunately hinders the development of new therapies. In this context, knowing the cause of binding site selectivity and the mechanism of action of inhibitors and substrates is crucial for drug discovery and optimization processes. In this paper, we provide a detailed computational investigation of the Qi site of T. cruzi cytochrome b to shed light on the molecular mechanism of action of known inhibitors and substrates. Our study emphasizes the action of inhibitors at the Qi site on a highly unstructured portion of cytochrome b that could be related to the biological function of the electron transport chain complex.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chagas Disease* / drug therapy
  • Cytochromes b / genetics
  • Electron Transport Complex III / metabolism
  • Humans
  • Mitochondrial Membranes
  • Trypanosoma cruzi* / metabolism

Substances

  • Cytochromes b
  • Electron Transport Complex III

Grants and funding

SM, GG, LS, and AD did the research as part of SINERGIA project, funded by the Swiss National Science (SNF) under the Grant Agreement CRSII5_183536. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.