Mitochondrial protein complexes: A single amino acid can jeopardize their stability
Removing a single amino acid can determine whether new proteins assemble into stable complexes within mitochondria. An enzyme carries out this precise trimming at the start of mitochondrial proteins. Without it, numerous protein complexes lose their stability, according to a study led by Dr. Nora Vögtle of Heidelberg University and Dr. Pitter Huesgen of the University of Freiburg. In their work…
A single amino acid removed from mitochondrial protein complexes can jeopardize their stability, according to a study published in Nature Structural & Molecular Biology. Dr. Nora Vögtle and Dr. Pitter Huesgen from Heidelberg University and the University of Freiburg led the research. The enzyme ICP55, which is crucial for protein maturation, trims off one additional amino acid after removing the N-terminus address sequence.
When ICP55 is absent, numerous protein complexes lose their stability, including respiratory chain complexes essential for cellular energy production and the HSP60 complex responsible for protein folding. The study, led by Dr. Vögtle and Dr. Huesgen, discovered that at least 107 imported human mitochondrial proteins undergo ICP55 processing.
Cells missing the enzyme exhibited reduced stability in respiratory chain, HSP60, ribosomal, and metabolic complexes. The research team also demonstrated that an extra amino acid directly destabilizes HSP60, causing its assembly to break down. This precise trimming of the N-terminus is fundamental for proteins to assemble into stable complexes, and disruptions in this process may contribute to mitochondrial diseases.
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