Katsutoshi Murao

Synthesis of formycin triphosphate and its incorporation into ribopolynucleotide by DNA-dependent RNA polymerase

Abstract The antibiotic formycin (F), an adenosine anlog, was chemically phosphorylated to give formycin 5′-triphosphate (FTP). FTP was tested as a substrate in the Escherichia coli RNA polymerase system using either deoxypolynucleotides with defined nucleotide sequences or natural DNAs as template. FTP could replace ATP when DNAs from calf thymus, salmon sperm, T2 and E. coli were used as template. However, the rate of synthesis of formycin-containing RNA was 47–68% of that of RNA from natural nucleoside triphosphates. When the deoxypolynucleotides such as poly d(A-T), poly (T-C) · d(A-G) and poly (T-G) · d(A-C) were used as templates, efficiency of synthesis of poly (F-U), poly (F-G) and poly (F-C) was 56, 94 and 67%, respectively, as compared to the synthesis of the corresponding poly (A-U), poly (A-G) and poly (A-C). This indicates that utilization of FTP as an ATP analog is affected by the base sequence of the template. The fidelity of the incorporation of FTP in place of ATP was confirmed by the analysis of the digest of the newly synthesized poly (F-U), poly (F-C) and poly (F-G) with bovine pancreatic or T1 ribonuclease. FpUp, FpCp and FpGp were the sole products from the digest of poly (F-U), poly (F-C) and poly (F-G) respectively.

Characterization of C+ located in the first position of the anticodon of Escherichia coli tRNAMet as N4-acetylcytidine

Abstract An unknown minor component present in the first position of the anticodon of Escherichia coli tRNAMet has been characterized as N 4 - acetylcytidine . The identity of the nucleoside was established by comparison of its ultraviolet absorption spectrum and thinlayer chromatographic mobility, and low- and high-resolution mass spectra with those of a chemically synthesized authentic sample.

Nucleotide sequences of serine tRNAs from Bacillus subtilis

Three B. subitilis serine tRNAs were sequenced including modified nucleosides. All the serine tRNAs contained 1-methyl-adenosine in the D-loop. As other characteristic modified nucleosides, 5-methoxyuridine was found in the first letter of the anticodon in the tRNA(UGA).