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Molecular basis for the differential interaction of plant mitochondrial VDAC proteins with tRNAs.

Salinas T, El Farouk-Ameqrane S, Ubrig E, Sauter C, Duchêne AM, Maréchal-Drouard L - Nucleic Acids Res. (2014)

Bottom Line: To further identify specific features and critical amino acids required for tRNA binding, 21 VDAC34 mutants were constructed and analyzed by northwestern.This allowed us to show that the β-barrel structure of VDAC34 and the first 50 amino acids that contain the α-helix are essential for RNA binding.Altogether the work shows that during evolution, plant mitochondrial VDAC proteins have diverged so as to interact differentially with nucleic acids, and this may reflect their involvement in various specialized biological functions.

View Article: PubMed Central - PubMed

Affiliation: Institut de Biologie Moléculaire des Plantes, UPR 2357 CNRS, associated with Strasbourg University, 12 rue du Général Zimmer 67084 Strasbourg cedex, France laurence.drouard@ibmp-cnrs.unistra.fr.

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Two Lysines and one Glycine present in the N-terminal region of VDAC34 are essential for the interaction with tRNA. Mutants with point mutations (M1–M7) are schematically represented. Amino acids are indicated by the one letter code. Quantification of interaction between mutant proteins and tRNA were done by NW experiments in presence of Arabidopsis thaliana cytosolic tRNAAla. Obtained values are represented on a diagram and are given in a summary table. They are the average of 2–10 independent experiments and correspond to the percentage of interaction of the mutant protein with tRNA compared to the wild-type VDAC34 interaction. Standard error is indicated for each value. Examples of NW experiments allowing the quantification of interactions are given as supplemental information (Supplemental Figure S4).
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Figure 5: Two Lysines and one Glycine present in the N-terminal region of VDAC34 are essential for the interaction with tRNA. Mutants with point mutations (M1–M7) are schematically represented. Amino acids are indicated by the one letter code. Quantification of interaction between mutant proteins and tRNA were done by NW experiments in presence of Arabidopsis thaliana cytosolic tRNAAla. Obtained values are represented on a diagram and are given in a summary table. They are the average of 2–10 independent experiments and correspond to the percentage of interaction of the mutant protein with tRNA compared to the wild-type VDAC34 interaction. Standard error is indicated for each value. Examples of NW experiments allowing the quantification of interactions are given as supplemental information (Supplemental Figure S4).

Mentions: Between positions 1 to 21, four amino acids differ between the two VDACs (Figure 3). Comparison of the physicochemical properties showed that one out of the four amino acids was not equivalent: at position 2 there is a Glycine residue (G2) in VDAC34 whereas in VDAC36 there is a Valine residue (Figure 3B). Consequently, two mutants were designed: mutant M1 corresponding to VDAC34 with a Valine instead of a Glycine at position 2 and mutant M2 introducing a Glycine at position 2 in VDAC36. Northwestern analysis showed that in mutant M1, the interaction was reduced 2-folds whereas reciprocally in mutant M2, the interaction was increased 2-folds compared to VDAC36 (Figure 5). This is in accordance with what was observed for mutants C4 and C5 (Figure 4B) and demonstrates the importance of the Glycine residue at position 2 for the interaction with tRNAs.


Molecular basis for the differential interaction of plant mitochondrial VDAC proteins with tRNAs.

Salinas T, El Farouk-Ameqrane S, Ubrig E, Sauter C, Duchêne AM, Maréchal-Drouard L - Nucleic Acids Res. (2014)

Two Lysines and one Glycine present in the N-terminal region of VDAC34 are essential for the interaction with tRNA. Mutants with point mutations (M1–M7) are schematically represented. Amino acids are indicated by the one letter code. Quantification of interaction between mutant proteins and tRNA were done by NW experiments in presence of Arabidopsis thaliana cytosolic tRNAAla. Obtained values are represented on a diagram and are given in a summary table. They are the average of 2–10 independent experiments and correspond to the percentage of interaction of the mutant protein with tRNA compared to the wild-type VDAC34 interaction. Standard error is indicated for each value. Examples of NW experiments allowing the quantification of interactions are given as supplemental information (Supplemental Figure S4).
© Copyright Policy - creative-commons
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4150812&req=5

Figure 5: Two Lysines and one Glycine present in the N-terminal region of VDAC34 are essential for the interaction with tRNA. Mutants with point mutations (M1–M7) are schematically represented. Amino acids are indicated by the one letter code. Quantification of interaction between mutant proteins and tRNA were done by NW experiments in presence of Arabidopsis thaliana cytosolic tRNAAla. Obtained values are represented on a diagram and are given in a summary table. They are the average of 2–10 independent experiments and correspond to the percentage of interaction of the mutant protein with tRNA compared to the wild-type VDAC34 interaction. Standard error is indicated for each value. Examples of NW experiments allowing the quantification of interactions are given as supplemental information (Supplemental Figure S4).
Mentions: Between positions 1 to 21, four amino acids differ between the two VDACs (Figure 3). Comparison of the physicochemical properties showed that one out of the four amino acids was not equivalent: at position 2 there is a Glycine residue (G2) in VDAC34 whereas in VDAC36 there is a Valine residue (Figure 3B). Consequently, two mutants were designed: mutant M1 corresponding to VDAC34 with a Valine instead of a Glycine at position 2 and mutant M2 introducing a Glycine at position 2 in VDAC36. Northwestern analysis showed that in mutant M1, the interaction was reduced 2-folds whereas reciprocally in mutant M2, the interaction was increased 2-folds compared to VDAC36 (Figure 5). This is in accordance with what was observed for mutants C4 and C5 (Figure 4B) and demonstrates the importance of the Glycine residue at position 2 for the interaction with tRNAs.

Bottom Line: To further identify specific features and critical amino acids required for tRNA binding, 21 VDAC34 mutants were constructed and analyzed by northwestern.This allowed us to show that the β-barrel structure of VDAC34 and the first 50 amino acids that contain the α-helix are essential for RNA binding.Altogether the work shows that during evolution, plant mitochondrial VDAC proteins have diverged so as to interact differentially with nucleic acids, and this may reflect their involvement in various specialized biological functions.

View Article: PubMed Central - PubMed

Affiliation: Institut de Biologie Moléculaire des Plantes, UPR 2357 CNRS, associated with Strasbourg University, 12 rue du Général Zimmer 67084 Strasbourg cedex, France laurence.drouard@ibmp-cnrs.unistra.fr.

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