A small polymerase ribozyme that can synthesize itself and its complementary strand.

Area of Science:

• Origin of Life
• RNA World Hypothesis
• Biochemistry

Background:

• Self-replication and evolution are key to life's origin.
• Existing RNA polymerase ribozymes are too large and complex for spontaneous emergence.

Purpose of the Study:

• To discover a small, self-replicating RNA polymerase ribozyme.
• To investigate RNA synthesis capabilities in minimal RNA motifs.

Main Methods:

• Discovered QT45 ribozyme from random sequence pools.
• Assessed RNA templated RNA synthesis using trinucleotide triphosphate substrates in eutectic ice.
• Determined fidelity and yield of synthesized RNA strands.

Main Results:

• QT45 (45-nucleotides) catalyzes RNA synthesis using triplet substrates.
• Achieved ~0.2% yield in 72 days for complementary strand and self-copy synthesis.
• Demonstrated 94.1% per-nucleotide fidelity in complementary strand synthesis.

Conclusions:

• Small RNA motifs can possess polymerase activity.
• Polymerase ribozymes may be more abundant in sequence space than previously assumed.
• Facilitates understanding of early RNA replication mechanisms in origin of life scenarios.