Novel mechanism of human mitochondrial ribosome formation

In a new study, researchers at the UK's Diamond Light Source Electron Bioimaging Centre have used cryo-electron microscopy for the first time to reveal how energy makers work during the formation of the human body

The results of this study were published in the February 19, 2021 issue of Science under the title "Mechanisms of Membrane Mitochondrial Protein Synthesis.

This paper reports the molecular mechanism of human mitochondrial membrane protein synthesis

This is a fundamental new understanding of how the human mitochondrial ribosome (mitoribosome) works, and could explain how mitochondria are affected by mutation and dysfunction that can lead to diseases such as deafness and diseases including cancer

Mitochondria are organelles within cells that serve as tiny but powerful energy factories in our bodies

Mitochondria are especially important in energy-hungry organs such as the heart, liver, muscles, and brain

Much of the energy production in mitochondria occurs in naturally evolved nanofactories that are integrated in specialized membranes

These nanofactories are composed of proteins that cooperate to transport ions and electrons to generate our body's chemical energy currency (ATP)

To solve this problem, mitochondria have their own protein-making machinery, the mitochondrial ribosome

Alexey Amunts, co-corresponding author of the paper and head of the Molecular Interaction Biology program at the Life Sciences Laboratory at Stockholm University, said:

"Seven years ago, our study of the yeast mitochondrial ribosome was called the resolution revolution

The term "resolution revolution" was coined after the first successful determination of mitochondrial ribosome structure in Science

This represents a methodological innovation in applying cryo-electron microscopy to understand molecular structure

However, the mitochondrial ribosome is a flexible molecular machine that requires relative motion of its parts to function

In the new study, therefore, the researchers used cryo-electron microscopy data acquisition at the Diamond Light Source Electron Bioimaging Center to obtain 30x more data, allowing them to characterize the process of protein synthesis and binding to membrane adapter proteins

Amunts added, "Our study elucidates the molecular mechanism of this dynamic, explains how mitochondrial ribosomes actually function to form cellular energy factories, and reveals that mitochondrial ribosomes are more flexible and active than previously thought

Yuriy Chaban, Principal Electron Microscopy Scientist at the Diamond Light Source Electron Bioimaging Centre, commented: "At Diamond Light Source, we are pushing the limits of physical and life science measurements, and thanks to our team, we can now make measurements

The sequencing of the human mitochondrial genome 40 years ago was a turning point in mitochondrial research, which postulated specific mechanisms for mitochondrial transmembrane protein synthesis
.

In fact, this discovered human mitochondrial ribosomal gating mechanism is a unique phenomenon
.
Therefore, these structural data provide a fundamental insight into how bioenergetic proteins are synthesized in vivo
.

source:

1.
Yuzuru Itoh et al.
Mechanism of membrane-tethered mitochondrial protein synthesis.
Science, 2021, doi:10.
1126/science.
abe0763.

2.
Mitochondria: New data sheds light on genesis of our body's powerhouses.
https://phys.
org/news/2021-02-mitochondria-genesis-body-powerhouses.
html