A Mosaic of RNA Binding and Protein Interaction Motifs in a Bifunctional Mitochondrial tRNA Import Factor from Leishmania tropica
IR@IICB: CSIR-Indian Institute of Chemical Biology, Kolkata
View Archive Info| Field | Value | |
| Title |
A Mosaic of RNA Binding and Protein Interaction
Motifs in a Bifunctional Mitochondrial tRNA
Import Factor from Leishmania tropica
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| Creator |
Home, Pratik
Mukherjee, Saikat Adhya, Samit |
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| Subject |
Molecular & Human Genetics
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| Description |
Proteins that participate in the import of cytosolic
tRNAs into mitochondria have been identified in several
eukaryotic species, but the details of their interactions
with tRNA and other proteins are unknown.
In the kinetoplastid protozoon Leishmania tropica,
multiple proteins are organized into a functional
import complex. RIC8A, a tRNA-binding subunit of
this complex, has a C-terminal domain that functions
as subunit 6b of ubiquinol cytochrome c reductase
(complex III). We show that the N-terminal domain,
unique to kinetoplastid protozoa, is structurally similar
to the appended S15/NS1 RNA-binding domain of
aminoacyl tRNA synthetases, with a helix–turn–helix
motif. Structure-guided mutagenesis coupled with
in vitro assays showed that helix a1 contacts tRNA
whereas helix a2 targets the protein for assembly
into the import complex. Inducible expression of
a helix 1-deleted variant in L. tropica resulted in formation
of an inactive import complex, while the helix
2-deleted variant was unable to assemble in vivo.
Moreover, a protein-interaction assay showed that
the C-terminal domain makes allosteric contacts
with import receptor RIC1 complexed with tRNA.
These results help explain the origin of the bifunctionality
of RIC8A, and the allosteric changes accompanying
docking and release of tRNA during import.
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| Date |
2008
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| Type |
Article
PeerReviewed |
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| Format |
application/pdf
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| Identifier |
http://www.eprints.iicb.res.in/152/1/NUCLEIC_ACIDS_RESEARCH%2C_36(17)%2C_5552%2D5561%2C2008[27].pdf
Home, Pratik and Mukherjee, Saikat and Adhya, Samit (2008) A Mosaic of RNA Binding and Protein Interaction Motifs in a Bifunctional Mitochondrial tRNA Import Factor from Leishmania tropica. Nucleic Acids Research, 36 (17). pp. 5552-5561. |
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| Relation |
http://dx.doi.org/10.1093/nar/gkn536
http://www.eprints.iicb.res.in/152/ |
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