The α-Subunit of Leishmania F1 ATP Synthase Hydrolyzes ATP in Presence of tRNA

Goswami, Srikanta and Adhya, Samit (2006) The α-Subunit of Leishmania F1 ATP Synthase Hydrolyzes ATP in Presence of tRNA. THE JOURNAL OF BIOLOGICAL CHEMISTRY, 281 (28). pp. 18914-18917.

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    Abstract

    Import of tRNAs into the mitochondria of the kinetoplastid protozoon Leishmania requires the tRNA-dependent hydrolysis of ATP leading to the generation of membrane potential through the pumping of protons. Subunit RIC1 of the inner membrane RNA import complex is a bi-functional protein that is identical to the �-subunit of F1F0 ATP synthase and specifically binds to a subset (Type I) of importable tRNAs. We show that recombinant, purified RIC1 is a Type I tRNA-dependent ATP hydrolase. The activity was insensitive to oligomycin, sensitive to mutations within the import signal of the tRNA, and required the cooperative interaction between the ATP-binding and C-terminal domains of RIC1. The ATPase activity of the intact complex was inhibited by anti-RIC1 antibody, while knockdown of RIC1 in Leishmania tropica resulted in deficiency of the tRNA-dependent ATPase activity of the mitochondrial inner membrane. Moreover, RIC1 knockdown extracts failed to generate a membrane potential across reconstituted proteoliposomes, as shown by a rhodamine 123 uptake assay, but activity was restored by adding back purified RIC1. These observations identify RIC1 as a novel form of the F1 ATP synthase �-subunit that acts as the major energy transducer fortRNA import.

    Item Type: Article
    URI: http://www.eprints.iicb.res.in/id/eprint/482
    Subjects: Molecular & Human Genetics
    Divisions: Indian Institute of Chemical Biology
    Depositing User: Mr Shyamal Nath
    Date Deposited: 02 Nov 2011 14:00
    Last Modified: 03 Feb 2012 12:14
    Official URL: http://www.jbc.org/content/281/28/18914.full.pdf+h...
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