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Reduced ribosomes of the apicoplast and mitochondrion of Plasmodium spp. and predicted interactions with antibiotics.

Gupta A, Shah P, Haider A, Gupta K, Siddiqi MI, Ralph SA, Habib S - Open Biol (2014)

Bottom Line: We carried out an analysis of the complement of core ribosomal protein subunits that are encoded by either the parasite organellar or nuclear genomes, accompanied by a survey of ribosome assembly factors for the apicoplast and mitochondrion.A cross-species comparison with other apicomplexan, algal and diatom species revealed compositional differences in apicomplexan organelle ribosomes and identified considerable reduction and divergence with ribosomes of bacteria or characterized organelle ribosomes from other organisms.Differences in predicted drug-ribosome interactions with some of the modelled structures suggested specificity of inhibition between the apicoplast and mitochondrion.

View Article: PubMed Central - PubMed

Affiliation: Division of Molecular and Structural Biology, CSIR-Central Drug Research Institute, Lucknow, India.

ABSTRACT
Apicomplexan protists such as Plasmodium and Toxoplasma contain a mitochondrion and a relic plastid (apicoplast) that are sites of protein translation. Although there is emerging interest in the partitioning and function of translation factors that participate in apicoplast and mitochondrial peptide synthesis, the composition of organellar ribosomes remains to be elucidated. We carried out an analysis of the complement of core ribosomal protein subunits that are encoded by either the parasite organellar or nuclear genomes, accompanied by a survey of ribosome assembly factors for the apicoplast and mitochondrion. A cross-species comparison with other apicomplexan, algal and diatom species revealed compositional differences in apicomplexan organelle ribosomes and identified considerable reduction and divergence with ribosomes of bacteria or characterized organelle ribosomes from other organisms. We assembled structural models of sections of Plasmodium falciparum organellar ribosomes and predicted interactions with translation inhibitory antibiotics. Differences in predicted drug-ribosome interactions with some of the modelled structures suggested specificity of inhibition between the apicoplast and mitochondrion. Our results indicate that Plasmodium and Toxoplasma organellar ribosomes have a unique composition, resulting from the loss of several large and small subunit proteins accompanied by significant sequence and size divergences in parasite orthologues of ribosomal proteins.

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A five-set Venn diagram showing the distribution of nuclear- or plastid-encoded ribosomal proteins that would constitute the plastid ribosomes of apicomplexans P. falciparum and T. gondii, red alga C. merolae, green alga C. reinhardtii and diatom T. pseudonana.
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RSOB140045F1: A five-set Venn diagram showing the distribution of nuclear- or plastid-encoded ribosomal proteins that would constitute the plastid ribosomes of apicomplexans P. falciparum and T. gondii, red alga C. merolae, green alga C. reinhardtii and diatom T. pseudonana.

Mentions: The L19 and L20 proteins have orthologues in Plasmodium and Toxoplasma with probable mitochondrial targeting sequences, but we found no orthologues of these with apicoplast targeting leaders (table 1 and figure 1). These are small proteins (approx. 120 amino acids each) and may hence be missed in a sequence similarity search. Several other 50S ribosomal proteins—L30, L31, L32 and L34—have mixed distributions in other organellar ribosomes [37,39,40], and we found no apicoplast or mitochondrial representatives of any of these proteins in apicomplexans.Figure 1.


Reduced ribosomes of the apicoplast and mitochondrion of Plasmodium spp. and predicted interactions with antibiotics.

Gupta A, Shah P, Haider A, Gupta K, Siddiqi MI, Ralph SA, Habib S - Open Biol (2014)

A five-set Venn diagram showing the distribution of nuclear- or plastid-encoded ribosomal proteins that would constitute the plastid ribosomes of apicomplexans P. falciparum and T. gondii, red alga C. merolae, green alga C. reinhardtii and diatom T. pseudonana.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4042851&req=5

RSOB140045F1: A five-set Venn diagram showing the distribution of nuclear- or plastid-encoded ribosomal proteins that would constitute the plastid ribosomes of apicomplexans P. falciparum and T. gondii, red alga C. merolae, green alga C. reinhardtii and diatom T. pseudonana.
Mentions: The L19 and L20 proteins have orthologues in Plasmodium and Toxoplasma with probable mitochondrial targeting sequences, but we found no orthologues of these with apicoplast targeting leaders (table 1 and figure 1). These are small proteins (approx. 120 amino acids each) and may hence be missed in a sequence similarity search. Several other 50S ribosomal proteins—L30, L31, L32 and L34—have mixed distributions in other organellar ribosomes [37,39,40], and we found no apicoplast or mitochondrial representatives of any of these proteins in apicomplexans.Figure 1.

Bottom Line: We carried out an analysis of the complement of core ribosomal protein subunits that are encoded by either the parasite organellar or nuclear genomes, accompanied by a survey of ribosome assembly factors for the apicoplast and mitochondrion.A cross-species comparison with other apicomplexan, algal and diatom species revealed compositional differences in apicomplexan organelle ribosomes and identified considerable reduction and divergence with ribosomes of bacteria or characterized organelle ribosomes from other organisms.Differences in predicted drug-ribosome interactions with some of the modelled structures suggested specificity of inhibition between the apicoplast and mitochondrion.

View Article: PubMed Central - PubMed

Affiliation: Division of Molecular and Structural Biology, CSIR-Central Drug Research Institute, Lucknow, India.

ABSTRACT
Apicomplexan protists such as Plasmodium and Toxoplasma contain a mitochondrion and a relic plastid (apicoplast) that are sites of protein translation. Although there is emerging interest in the partitioning and function of translation factors that participate in apicoplast and mitochondrial peptide synthesis, the composition of organellar ribosomes remains to be elucidated. We carried out an analysis of the complement of core ribosomal protein subunits that are encoded by either the parasite organellar or nuclear genomes, accompanied by a survey of ribosome assembly factors for the apicoplast and mitochondrion. A cross-species comparison with other apicomplexan, algal and diatom species revealed compositional differences in apicomplexan organelle ribosomes and identified considerable reduction and divergence with ribosomes of bacteria or characterized organelle ribosomes from other organisms. We assembled structural models of sections of Plasmodium falciparum organellar ribosomes and predicted interactions with translation inhibitory antibiotics. Differences in predicted drug-ribosome interactions with some of the modelled structures suggested specificity of inhibition between the apicoplast and mitochondrion. Our results indicate that Plasmodium and Toxoplasma organellar ribosomes have a unique composition, resulting from the loss of several large and small subunit proteins accompanied by significant sequence and size divergences in parasite orthologues of ribosomal proteins.

Show MeSH