The origin and early evolution of nucleic acid polymerases

Area of Science:

• Molecular Biology
• Evolutionary Biology
• Biochemistry

Background:

• The origin of cellular life and the evolution of core molecular machinery like RNA polymerases are key research areas.
• The hypothesis posits that the bacterial RNA polymerase beta' subunit retains vestiges of an ancestral RNA-dependent RNA polymerase.

Purpose of the Study:

• To investigate the presence of ancestral RNA-dependent RNA polymerase components within eubacterial RNA polymerases.
• To analyze conserved sequences and their potential functional implications in RNA polymerases and related enzymes.

Main Methods:

• Comparative sequence analysis of DNA-dependent RNA polymerases across three cellular lineages.
• Identification of conserved amino acid sequences, specifically an eight-amino-acid motif.
• Characterization of optimal conditions for avian myeloblastosis virus reverse transcriptase activity.

Main Results:

• A highly conserved eight-amino-acid sequence was identified in DNA-dependent RNA polymerases from all three cellular lineages.
• This conserved sequence is also present in the RNA-binding sites of E. coli polynucleotide phosphorylase and the S1 ribosomal protein.
• Optimal conditions for avian myeloblastosis virus reverse transcriptase replicase activity were determined.

Conclusions:

• The conserved sequence suggests a potential evolutionary link between ancestral RNA replication machinery and modern RNA polymerases.
• Further research into RNA polymerases and reverse transcriptases can illuminate early life evolution and enzyme specificity modifications.