Amazing stuff!
"This story begins several billion years ago. There's only chemistry, no biology – that is, plenty of chemical compounds exist on Earth, but life hasn’t yet emerged. Then, among myriads of randomly self-assembled chemical structures, one tiny RNA molecular machine reveals itself as perfectly suitable for creating bonds between activated amino acids, the building blocks of future proteins. It’s a turning point in the story of our planet: The synthesis of proteins, biological molecules essential for life, can now begin ...
As to the primordial peptide-bond-making machine, they discovered that it’s still present in virtually every cell of all living organisms, from bacteria to plants and animals, including ourselves. ...
“The ribosome is an enormous macromolecule that is not at all symmetrical; at its heart, it contains two semisymmetrical elements joined together to form a pocket.” “We were particularly struck by the fact that this pocket is found in the ribosomes of all organisms. And this is where all the action takes place – it’s where all peptide bonds that create the chain of linked amino acids making up a protein are formed. That’s why this basic machinery seems to have persisted unchanged throughout evolution.” Meet the protoribosome: That’s what the scientists call this pocket-like structure. ...
because it performed useful functions and, thanks to RNA’s intrinsic capabilities, it could self-replicate. ...
That was the beginning of proteins, some of which then proved useful in stabilizing and bolstering the protoribosome itself. The proteins kept adding to the protoribosome’s structure, enabling it to evolve into the sophisticated protein-making factory it is today."
As to the primordial peptide-bond-making machine, they discovered that it’s still present in virtually every cell of all living organisms, from bacteria to plants and animals, including ourselves. ...
“The ribosome is an enormous macromolecule that is not at all symmetrical; at its heart, it contains two semisymmetrical elements joined together to form a pocket.” “We were particularly struck by the fact that this pocket is found in the ribosomes of all organisms. And this is where all the action takes place – it’s where all peptide bonds that create the chain of linked amino acids making up a protein are formed. That’s why this basic machinery seems to have persisted unchanged throughout evolution.” Meet the protoribosome: That’s what the scientists call this pocket-like structure. ...
because it performed useful functions and, thanks to RNA’s intrinsic capabilities, it could self-replicate. ...
That was the beginning of proteins, some of which then proved useful in stabilizing and bolstering the protoribosome itself. The proteins kept adding to the protoribosome’s structure, enabling it to evolve into the sophisticated protein-making factory it is today."
From the abstract:
"Although the mode of action of the ribosomes, the multi-component universal effective protein-synthesis organelles, has been thoroughly explored, their mere appearance remained elusive. Our earlier comparative structural studies suggested that a universal internal small RNA pocket-like segment called by us the protoribosome, which is still embedded in the contemporary ribosome, is a vestige of the primordial ribosome. Herein, after constructing such pockets, we show using the "fragment reaction" and its analyses by MALDI-TOF and LC–MS mass spectrometry techniques, that several protoribosome constructs are indeed capable of mediating peptide-bond formation. These findings present strong evidence supporting our hypothesis on origin of life and on ribosome's construction, thus suggesting that the protoribosome may be the missing link between the RNA dominated world and the contemporary nucleic acids/proteins life."
Origin of life: protoribosome forms peptide bonds and links RNA and protein dominated worlds (open access)
The protoribosome concept
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