In vitro selection of a deoxyribozyme that can utilize multiple substrates

Area of Science:

• Biochemistry
• Molecular Biology
• Origin of Life Studies

Background:

• Deoxyribozymes are DNA molecules with catalytic activity.
• The formation of internucleotide linkages is crucial for nucleic acid replication.
• Understanding early ligation mechanisms provides insight into the origin of life.

Purpose of the Study:

• To select deoxyribozymes that catalyze internucleotide phosphorothioester bond formation.
• To investigate the substrate specificity of these selected deoxyribozymes.
• To infer properties of early replicase enzymes.

Main Methods:

• In vitro selection from a random DNA sequence pool.
• Screening against five distinct oligonucleotide substrates with a common hexanucleotide terminus.
• Analysis of deoxyribozyme-substrate interactions and secondary structure formation.

Main Results:

• Successfully selected deoxyribozymes capable of catalyzing phosphorothioester linkage formation.
• Selected deoxyribozyme ligases demonstrated activity with all five tested substrates, though with varying efficiencies.
• Evidence suggests that secondary structures in deoxyribozymes facilitate differential binding to various oligonucleotide substrates.

Conclusions:

• Deoxyribozyme ligases can accommodate diverse oligonucleotide substrates through adaptable secondary structures.
• This adaptability supports the hypothesis that early replicases possessed broad substrate binding capabilities.
• The findings contribute to understanding primitive nucleic acid replication mechanisms.