2'-Deoxy-2'-fluorouridine-5'-triphosphates: a possible substrate for E. coli RNA polymerase

Area of Science:

• Biochemistry
• Molecular Biology
• Enzymology

Background:

• RNA polymerase is a crucial enzyme for transcription.
• Nucleotide triphosphates (NTPs) are the substrates for RNA synthesis.
• The divalent cation, typically magnesium (Mg++), is essential for RNA polymerase activity.

Purpose of the Study:

• To investigate the substrate capability of deoxyuridine triphosphate analog (dUflTP) in Escherichia coli RNA polymerase transcription.
• To determine if dUflTP can replace uridine triphosphate (UTP) under specific conditions.
• To evaluate the impact of manganese (Mn++) as a divalent cation on transcription with dUflTP.

Main Methods:

• In vitro transcription assays were performed using purified E. coli RNA polymerase.
• Poly(dAT) was used as a synthetic template.
• Deoxyuridine triphosphate analog (dUflTP) was tested as a substrate, replacing UTP.
• The reaction conditions were varied to include Mn++ instead of Mg++ as the divalent cation.

Main Results:

• dUflTP was successfully utilized as a substrate by E. coli RNA polymerase.
• dUflTP replaced UTP effectively when Mn++ was the divalent cation.
• Transcription levels using dUflTP with Mn++ reached 55% of the levels observed with UTP and Mg++.

Conclusions:

• dUflTP can function as a substrate in E. coli RNA polymerase-mediated transcription.
• The presence of Mn++ is critical for dUflTP incorporation, suggesting altered enzyme kinetics or substrate binding.
• The fluoro analog dUflTP offers a potential tool for studying transcription mechanisms, albeit with reduced efficiency compared to UTP.