[Polycytidylic matrix complex formation with complementary and noncomplementary purine nucleoside triphosphates]

Area of Science:

• Biochemistry
• Molecular Biology
• Polymer Chemistry

Background:

• Non-enzymatic nucleic acid synthesis is crucial for understanding early life.
• Polynucleotide complexes can exhibit selective monomer incorporation.
• Understanding misincorporation provides insights into fidelity mechanisms.

Purpose of the Study:

• To quantify the misincorporation of adenosine triphosphate (ATP) into a poly(C):GTP complex.
• To investigate the relationship between ATP concentration and misincorporation rate.
• To elucidate the factors governing non-enzymatic misincorporation.

Main Methods:

• Utilized radiolabeled H3-ATP to measure misincorporation.
• Varied ATP total concentration from 6x10^-6 M to 4.5x10^-3 M.
• Analyzed the poly(C):GTP complex formation and stability.

Main Results:

• Misincorporation (alpha) increased asymptotically with rising ATP concentration, reaching a plateau.
• Maximum misincorporation observed was approximately one adenilic residue per 1400 guanilic residues.
• No ATP incorporation was detected in the 2 poly(C):GTP complex.

Conclusions:

• Non-enzymatic misincorporation is significantly influenced by monomer stacking interactions.
• Differences in binding affinities between complementary and non-complementary monomers affect fidelity.
• These findings contribute to understanding the chemical basis of prebiotic nucleic acid replication.