Plasmodium, the Apicomplexa outlier when it comes to protein synthesis

Abstract

Plasmodium is an obligate intracellular parasite that makes numerous interactions with different hosts during its elaborate life cycle. This is also the case for other parasites that belong to the same phylum Apicomplexa. In this study, we identified bioinformatically the components of the multi-synthetase complexes (MSC) of several Apicomplexa parasites. By using AlphaFold2 modeling to compare their assembly, it appears that none of these MSCs resemble those identified in Plasmodium. In particular, the discrepancies between the core components of Plasmodium complexes, tRip and its homologs indicate that tRip-dependent exogenous tRNA import is not conserved in the other Apicomplexa parasites. Based on this observation, we looked for obvious differences that could explain this singularity in Plasmodium. The content of tRNA genes and amino acid usage in the different genomes highlighted the originality of Plasmodia translation. This is evident with respect to asparagine amino acid, which is highly used in the Plasmodium proteomes, and the scarcity of tRNAAsn required for protein synthesis, regardless of long homorepeats or AT content of the genomes.