The Alpha-subunit of Leishmania F1 Atp Synthase Hydrolyzes Atp in Presence of Trna.
From: Genetic Engineering Laboratory, Indian Institute of Chemical Biology, 4 Raja S.C. Mullick Road, Calcutta 700032, India.
The Journal of biological chemistry
- Publish Date: Jul 2006
- ISSN: 0021-9258
- Volume: 281
- Issue: 28
- Pages: 18914-7
- Medium: Print
- Language: English
- Citation (JAMA): Goswami Srikanta, Adhya Samit, et al. The Alpha-subunit of Leishmania F1 Atp Synthase Hydrolyzes Atp in Presence of Trna.. J. Biol. Chem. Jul 2006;281:18914-7
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 alpha-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 alpha-subunit that acts as the major energy transducer for tRNA import.
Mesh Headings (Keywords): Adenosine Triphosphate, Animals, Base Sequence, Hydrolysis, Intracellular Membranes, Leishmania tropica, Liposomes, Molecular Sequence Data, Oligomycins, Proton-Translocating ATPases, Protons, RNA, RNA, Transfer, Recombinant Proteins, Rhodamine 123
Check for Full Text / PubMed Unique Identifier (PMID): 16735512
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