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PubMed · 12861008

"Ping-pong" interactions between mitochondrial tRNA import receptors within a multiprotein complex.

Subhendra Nath Bhattacharyya·Saibal Chatterjee·Srikanta Goswami·Gayatri Tripathi·Sailendra Nath Dey·Samit Adhya
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Abstract

The mitochondrial genomes of a wide variety of species contain an insufficient number of functional tRNA genes, and translation of mitochondrial mRNAs is sustained by import of nucleus-encoded tRNAs. In Leishmania, transfer of tRNAs across the inner membrane can be regulated by positive and negative interactions between them. To define the factors involved in such interactions, a large multisubunit complex (molecular mass, approximately 640 kDa) from the inner mitochondrial membrane of the kinetoplastid protozoon Leishmania, consisting of approximately 130-A particles, was isolated. The complex, when incorporated into phospholipid vesicles, induced specific, ATP- and proton motive force-dependent transfer of Leishmania tRNA(Tyr) as well as of oligoribonucleotides containing the import signal YGGYAGAGC. Moreover, allosteric interactions between tRNA(Tyr) and tRNA(Ile) were observed in the RNA import complex-reconstituted system, indicating the presence of primary and secondary tRNA binding sites within the complex. By a combination of antibody inhibition, photochemical cross-linking, and immunoprecipitation, it was shown that binding of tRNA(Ile) to a 21-kDa component of the complex is dependent upon tRNA(Tyr), while binding of tRNA(Tyr) to a 45-kDa component is inhibited by tRNA(Ile). This "ping-pong" mechanism may be an effective means to maintain a balanced tRNA pool for mitochondrial translation.

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Allosteric SiteAmino Acid MotifsAnimalsBlotting, WesternCross-Linking ReagentsElectrophoresis, Polyacrylamide GelGlycerolImmunohistochemistryIntracellular MembranesKineticsLeishmaniaLightMicroscopy, ElectronMitochondriaModels, BiologicalPhospholipidsPrecipitin TestsProtein BindingProtein BiosynthesisRNA, TransferJournal ArticleResearch Support, Non-U.S. Gov't

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Subhendra Nath Bhattacharyya, Saibal Chatterjee, Srikanta Goswami, Gayatri Tripathi, Sailendra Nath Dey, Samit Adhya. 2003. "Ping-pong" interactions between mitochondrial tRNA import receptors within a multiprotein complex.. https://doi.org/10.1128/mcb.23.15.5217-5224.2003

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