Prebiotic chemical origin of biomolecular complementarity

Area of Science:

• Astrobiology
• Origin of Life Studies
• Prebiotic Chemistry

Background:

• The early Earth lacked a protective ozone layer, exposing it to intense UV radiation and very low energy electrons (vLEEs).
• This harsh environment necessitated the proliferation of molecules intrinsically stable against these damaging agents.
• Such stable molecules could have evolved into the complex building blocks of life.

Purpose of the Study:

• To investigate the stability of nucleobases and their complementary pairs under early Earth conditions.
• To determine if complementary base pairing enhances molecular stability against UV photons and vLEEs.
• To understand the role of base pairing in the chemical evolution of life's precursors.

Main Methods:

• Examined the inherent stability of individual nucleobases.
• Assessed the stability of complementary nucleobase pairs.
• Simulated the effects of shortwave UV photons and vLEEs on nucleobases and their pairs.

Main Results:

• Nucleobases exhibit enhanced stability when present as complementary pairs.
• Complementary base pairing significantly increases resistance to UV photons and vLEEs.
• This enhanced stability suggests a mechanism for nucleobase survival and evolution.

Conclusions:

• Complementary base pairing was crucial for nucleobase survival and proliferation on the early Earth.
• Base pairing provided essential molecular stability in a harsh prebiotic environment.
• This stability is a key aspect of chemical evolution leading to the origin of life.