In vivo formation of Plasmodium falciparum ribosomal stalk - a unique mode of assembly without stable heterodimeric intermediates.

Journal article

BACKGROUND: The ribosomal stalk composed of P-proteins constitutes a structure on the large ribosomal particle responsible for recruitment of translation factors and stimulation of factor-dependent GTP hydrolysis during translation. The main components of the stalk are P-proteins, which form a pentamer. Despite the conserved basic function of the stalk, the P-proteins do not form a uniform entity, displaying heterogeneity in the primary structure across the eukaryotic lineage. The P-proteins from protozoan parasites are among the most evolutionarily divergent stalk proteins. METHODS: We have assembled P-stalk complex of Plasmodium falciparum in vivo in bacterial system using tricistronic expression cassette and provided its characteristics by biochemical and biophysical methods. RESULTS: All three individual P-proteins, namely uL10/P0, P1 and P2, are indispensable for acquisition of a stable structure of the P stalk complex and the pentameric uL10/P0-(P1-P2)₂form represents the most favorable architecture for parasite P-proteins. CONCLUSION: The formation of P. falciparum P-stalk is driven by trilateral interaction between individual elements which represents unique mode of assembling, without stable P1-P2 heterodimeric intermediate. GENERAL SIGNIFICANCE: On the basis of our mass-spectrometry analysis supported by the bacterial two-hybrid assay and biophysical analyses, a unique pathway of the parasite stalk assembling has been proposed. We suggest that the absence of P1/P2 heterodimer, and the formation of a stable pentamer in the presence of all three proteins, indicate a one-step formation to be the main pathway for the vital ribosomal stalk assembly, whereas the P2 homo-oligomer may represent an off-pathway product with physiologically important nonribosomal role.

Authors: Wawiórka, L; Krokowski, D; Gordiyenko, Y; Krowarsch, D; Robinson, C

• Publication status: Published
• Publisher: Elsevier
• Journal: Biochimica et biophysica acta
• Volume: 1850
• Issue: 1
• Pages: 150-158
• Publication date: 2015-01-01
• DOI: 10.1016/j.bbagen.2014.10.015
• EISSN: 1872-8006
• ISSN: 0006-3002
• Language: English
• Keywords: Malaria; Ribosomes; Ribosomal P proteins; Ribosomal stalk; Protein complexes; Protein–protein interactions