Investigating Amino Acids in Water: New Insights

An international team of scientists have utilized photoelectron circular dichroism (PECD) to study alanine, a chiral amino acid, in water. This research reveals how alanine's molecular structure changes with pH levels and demonstrates the potential of PECD for understanding solvated chiral molecules under biologically relevant conditions.
 

Key Aspects

• Chirality in Nature: Chirality refers to objects that cannot be superimposed on their mirror images, like left and right hands. Many essential biomolecules are chiral, and their chirality plays a key role in determining their function.
• Photoelectron Circular Dichroism (PECD): A technique used to study chiral molecules by observing asymmetries in photoelectron emission upon ionization of the molecules circularly polarized light.
• Aqueous-Phase Alanine: The study focuses on alanine, the simplest chiral amino acid, in water, and highlights the sensitivity of PECD to changes in solution pH.
• Biological Relevance: Understanding chiral molecules in water is crucial for developing new insights into biochemical processes and better understanding the behavior of life-essential molecules.

Understanding Chirality and Its Importance

Chirality is a property found in many natural objects, from seashells to amino acids. In biochemistry, chirality is significant because many biomolecules, including proteins and DNA, are chiral. These molecules often exist solely in only one of their mirror-image forms in living organisms. This origins of this “homochirality of life” remain a mystery.

The Role of PECD in Chiral Studies

Photoelectron circular dichroism (PECD) is a technique that allows scientists to differentiate between the mirror-image forms of chiral molecules. Unlike traditional methods, PECD provides a more pronounced and sensitive measurement of these differences, making it a useful tool for studying chiral molecules.

Alanine in Water: A New Frontier

In this study, the researchers from the department of Molecular Physics at the Fritz Haber Institute of the Max Planck Society and collaboration institutes, applied PECD aqueous-phase chiral molecules for the first time, demonstrating that PECD may be used to study dilute aqueous solutions of biochemically relevant chiral molecules. They discovered that alanine's response to PECD varies with its molecular structure, which changes with the pH of the solution. This finding opens new avenues for studying how chiral molecules behave in aqueous environments, which is important for understanding biochemical processes. This study constitutes an important first step toward developing PECD as a powerful probe of chiral molecules in solution.

Implications for Biochemistry

The ability to study chiral molecules in water using PECD has implications for biochemistry. It provides insights into how these molecules interact with their environment, potentially influencing their function in biological systems. This research contributes to understanding the complexities of life at the molecular level, offering a new perspective on the behavior of essential biomolecules in their natural, aqueous state.