Distinct localization of chiral proofreaders resolves organellar translation conflict in plants.

Proceedings of the National Academy of Sciences of the United States of America 2023 Jun 13

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Plants have two endosymbiotic organelles originated from two bacterial ancestors. The transition from an independent bacterium to a successful organelle would have required extensive rewiring of biochemical networks for its integration with archaeal host. Here, using Arabidopsis as a model system, we show that plant D-aminoacyl-tRNA deacylase 1 (DTD1), of bacterial origin, is detrimental to organellar protein synthesis owing to its changed tRNA recognition code. Plants survive this conflict by spatially restricting the conflicted DTD1 to the cytosol. In addition, plants have targeted archaeal DTD2 to both the organelles as it is compatible with their translation machinery due to its strict D-chiral specificity and lack of tRNA determinants. Intriguingly, plants have confined bacterial-derived DTD1 to work in archaeal-derived cytosolic compartment whereas archaeal DTD2 is targeted to bacterial-derived organelles. Overall, the study provides a remarkable example of the criticality of optimization of biochemical networks for survival and evolution of plant mitochondria and chloroplast.

Citation

Pradeep Kumar, Kandhalu Sagadevan Dinesh Babu, Avinash Kumar Singh, Dipesh Kumar Singh, Aswan Nalli, Shivapura Jagadeesha Mukul, Ankit Roy, Mohd Mazeed, Bakthisaran Raman, Shobha P Kruparani, Imran Siddiqi, Rajan Sankaranarayanan. Distinct localization of chiral proofreaders resolves organellar translation conflict in plants. Proceedings of the National Academy of Sciences of the United States of America. 2023 Jun 13;120(24):e2219292120