The pre-RNA/DNA World

[Chip (OP)]

Amino acids self-assemble and peptides_proteins self-replicate !

It's all very simple really and I don't not believe in a RNA-world !

Let's dive into how amino acids assemble into proteins, including prions.

*Amino Acids: The Building Blocks*

Amino acids are organic compounds consisting of:

1. Central carbon atom (Cα)
2. Amino group (-NH2)
3. Carboxyl group (-COOH)
4. Side chain (R group), unique to each amino acid

*Amino Acid Assembly*

The assembly of amino acids into proteins involves:

1. *Peptide Bond Formation*: Amino acids link together through peptide bonds, formed between the carboxyl group of one amino acid and the amino group of another.
2. *Polypeptide Chain*: Amino acids linked together form a polypeptide chain.
3. *Primary Structure*: The sequence of amino acids determines the protein's primary structure.
4. *Secondary Structure*: Hydrogen bonds between amino acids create alpha-helices and beta-sheets.
5. *Tertiary Structure*: Interactions between side chains (R groups) and secondary structures stabilize the protein's 3D shape.

*Factors Influencing Amino Acid Assembly*

1. *Sequence*: Amino acid sequence dictates protein structure and function.
2. *Hydrophobic Interactions*: Non-polar side chains interact, influencing protein folding.
3. *Electrostatic Interactions*: Charged side chains interact, affecting protein stability.
4. *Hydrogen Bonding*: Interactions between amino acids stabilize secondary structures.
5. *Environmental Factors*: pH, temperature, and solvent conditions influence protein folding.

*Specific to Prion Assembly*
Prion proteins (PrP) have a unique sequence that allows for:

1. *Beta-Rich Structure*: PrP has a high proportion of beta-sheets, making it prone to misfolding.
2. *Hydrophobic Interactions*: Non-polar side chains in PrP facilitate aggregation.
3. ** templated Assembly**: Misfolded PrP (PrP^Sc) acts as a template for normal PrP (PrP^C) to misfold.

How would you like to explore this topic further?

The formation of amino acids is a topic rooted in biochemistry and evolutionary biology, and it is believed to have occurred through several key processes in Earth's early environment. Here are some primary theories and experiments that shed light on how amino acids could have formed:

1. Miller-Urey Experiment: In 1953, Stanley Miller and Harold Urey conducted an experiment simulating early Earth conditions. They created an atmosphere containing methane, ammonia, hydrogen, and water vapor, then introduced electrical sparks to mimic lightning. This experiment produced several amino acids, demonstrating that organic molecules could form from inorganic precursors under conditions thought to be similar to those of early Earthal Vents**: Another hypothesis suggests that amino acids could have formed near hydrothermal vents on the ocean floor. These vents provide a rich environment of minerals and energy sources that could facilitate the synthesis of organic compounds, including amino acids. Research indicates that the unique conditions around these vents could lead to the formation of complex organic molecules  .


2. **Extraterome theories propose that amino acids may have been delivered to Earth via meteorites or comets. Studies of carbonaceous meteorites have shown that they contain amino acids and other organic compounds, suggesting that the building blocks of life might be widespread in the universe and could have contributed to the emergence of life on Earth  .


3. **Natural Synthesis on Prebioesearch has focused on the possibility that amino acids could have formed through simpler chemical reactions that occurred in various environments, such as on the surface of minerals or through reactions facilitated by ultraviolet light. This perspective highlights the versatility of chemical pathways available in prebiotic conditions  .



For a more in-depth exploration of these theories ding the formation of amino acids, you can refer to the following sources:

Miller-Urey Experiment Overview

Extraterrestrial Origins of Amino Acids

Hydrothermal Vents and Organic Chemistry


Copilot:

Amino acids, the building blocks of life, likely formed in the early Earth's environment through a mix of chemical reactions. Here's a simplified breakdown:

### **Primordial Soup Theory:**

1. **Atmospheric Conditions**: The early Earth's atmosphere was rich in methane, ammonia, water vapor, and hydrogen. These gases provided the raw materials for amino acid formation.

2. **Energy Sources**: Lightning, ultraviolet radiation, and volcanic activity provided energy to drive chemical reactions.

3. **Miller-Urey Experiment**: In 1953, Stanley Miller and Harold Urey simulated early Earth conditions in a lab.

They passed electric sparks through a mixture of methane, ammonia, hydrogen, and water vapor, producing amino acids.

This experiment suggested that amino acids could form naturally under the right conditions.

### **Deep-Sea Hydrothermal Vents:**

1. **Hydrothermal Vents**: These underwater geysers release mineral-rich, superheated water. The extreme conditions and chemical gradients at these vents create a favorable environment for amino acid synthesis.

2. **Mineral Catalysts**: The minerals present in these vents could act as catalysts, helping to drive the formation of amino acids from simple molecules.

### **Extraterrestrial Origins:**

1. **Meteorites**: Some scientists believe that amino acids may have been delivered to Earth by meteorites. Studies of meteorites have found that they contain amino acids, suggesting that these building blocks of life might have formed in space and been brought to Earth.

2. **Interstellar Dust**: Amino acids have also been detected in interstellar dust clouds, further supporting the idea that they might have an extraterrestrial origin.

In essence, a combination of early Earth conditions, possibly enhanced by extraterrestrial contributions, likely triggered the formation of amino acids. This set the stage for the emergence of life as we know it.

What's next on your curiosity list?