# Cryo-EM structure of the Trypanosoma brucei ATOM protein-import complex resolved at 2.8 Å

- Published: 2026-11-13 06:04 UTC
- Section: Life & Health › Biology & biochemistry
- Tags: ATOM complex structure, Trypanosoma brucei, mitochondrial protein import, cryoelectron microscopy, translocase of the outer membrane, TOM complex, eukaryotic evolution, 2.8 Å resolution
- URL: https://realtech.media/news/rt-7856c2ed949fc01a200d206e_cryo_em_structure/

**Authors resolved the ATOM complex of the parasite T. brucei, which replaces TOM, and found an extra subunit and a dimeric channel like that of fungal and animal TOM.**

![Cryo-EM structure of the Trypanosoma brucei ATOM protein-import complex resolved at 2.8 Å](https://realtech.media/media/2026/11/a3b102131e805499.jpg)
*Tina Saey, Wikimedia Commons, CC BY 2.0*

Researchers determined the cryoelectron microscopy structure of the ATOM complex of the protozoan parasite Trypanosoma brucei at 2.8 Å resolution, according to a report in Proceedings of the National Academy of Sciences [1]. ATOM is the atypical translocase of the outer membrane. In T. brucei it replaces the canonical TOM complex, which mediates import of most mitochondrial preproteins in fungi and metazoans [1]. Its composition differs substantially from those complexes.

The structure resolves all previously identified components together with an additional, previously uncharacterized subunit [1]. Despite the divergent composition, ATOM retains a dimeric channel architecture and a protein-conducting pathway that closely resembles those of opisthokont TOM complexes [1]. The authors conclude that the core mechanism of mitochondrial protein translocation was established early in eukaryotic evolution.

The receptor and intermembrane-space regions, by contrast, have distinct architectures. The authors describe this as extensive evolutionary diversification with multiple examples of convergent evolution [1]. The work gives a near-atomic view of the ATOM translocase and of how the mitochondrial protein import machinery originated, was conserved and diversified across eukaryotes.

## Sources

1. [Proceedings of the National Academy of Sciences](https://doi.org/10.1073/pnas.2622689123)

---

Source: RealTech, realtech.media — https://realtech.media/news/rt-7856c2ed949fc01a200d206e_cryo_em_structure/