Peptide molecules for treating mitochondrial pathologies

The invention refers to peptide molecules consisting of a sequence of aminoacids that is comprised in the C-terminal domain of a mitochondrial leucyl-tRNA synthetase for medical use, in particular for use in the treatment of mitochondrial diseases, and to a pharmaceutical compositions comprising the above peptide molecules and appropriate diluents and/or excipients. The invention also refers to peptide molecules capable of suppressing the respiratory defect of human and/or yeast cells mutated in a mitochondrial gene coding for tRNA and to nucleotide sequences coding for the above peptides.