Xeno Amino Acids: A Look into Biochemistry as We Do Not Know It
Sean M Brown1, Christopher Mayer-Bacon1, Stephen Freeland1
1Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, MD 21250, USA.
Life (Basel, Switzerland)
|December 23, 2023
Summary
Amino acids are key targets for astrobiology research, as they are readily available building blocks for potential extraterrestrial life. Research explores alternative amino acid structures and side chains, highlighting the roles of chemical evolution and biological adaptation.
Area of Science:
- Astrobiology
- Biochemistry
- Origin of Life Studies
Background:
- Investigates the fundamental building blocks of life, specifically amino acids, and their potential role in extraterrestrial origins.
- Examines Earth's biochemical reliance on L-alpha-amino acids and explores whether alternative structures could support life.
- Considers the diversity of amino acid side chains and the factors influencing their selection in biological systems.
Purpose of the Study:
- To assess the likelihood of amino acids serving as building blocks for life beyond Earth.
- To evaluate whether the specific L-alpha-amino acid subclass and side chains used by Earth life are universal requirements.
- To identify opportunities for laboratory and computational research in exploring alternative amino acid alphabets and their impact on protein structures.
Main Methods:
- Review of current knowledge on amino acid availability and chemical attractors for abiogenesis.
- Analysis of the physicochemical properties and potential disadvantages of alternative amino acid backbones.
- Examination of evolutionary and physicochemical factors influencing the selection of amino acid side chains in extant life.
Main Results:
- Amino acids appear to be readily available and plausible chemical attractors for the origin of life.
- While the L-alpha-amino acid structure is understood for Earth life, alternative backbones may be disadvantageous rather than impossible.
- Numerous alternative side chains exist, with biological evolution playing a more significant role than physicochemical constraints in shaping the current amino acid set.
Conclusions:
- Amino acids remain critical targets for astrobiological research, with potential for diverse chemical origins.
- Future research should focus on exploring 'xeno peptides' and the functional diversity arising from alternative amino acid alphabets.
- Merging laboratory experiments and computational approaches is key to understanding the universe of protein folds and functions.
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