Enzymatic polymerization of 5-mercuriuridine-5′-diphosphate with polynucleotide phosphorylase from E. coli

Organomercury Nucleic Acids: Past, Present and Future

“…With relatively weakly coordinating ligands, such as acetato or chlorido, organomercury nucleotides are potent inhibitors of both DNA and RNA polymerases, in all likelihood owing to coordination of Hg II to a critical sulfhydryl group. [3,13,14] In the presence of a thiol ligand, polymerization proceeds smoothly albeit with some concomitant demercuration. [15] Interestingly, different enzymes exhibit different requirements for the thiol ligand -although 2-mercaptoethanol is the ligand of choice in most cases, some enzymes, notably calf thymus terminal deoxynucleotidyl transferase, prefer a sterically less demanding ligand such as methane-or ethanethiol.…”

“…[15] Interestingly, different enzymes exhibit different requirements for the thiol ligand -although 2-mercaptoethanol is the ligand of choice in most cases, some enzymes, notably calf thymus terminal deoxynucleotidyl transferase, prefer a sterically less demanding ligand such as methane-or ethanethiol. [3] Enzymatic polymerization of 5-mercuripyrimidine nucleotides has been proven with both template-directed [16] as well as template-independent [13] polymerases. In the former case, 5mercuriuridine-5'-triphosphate was readily incorporated on a poly[d(AT)] but not on a poly(dG)•poly(dC) template while the opposite is true for 5-mercuricytidine-5'-triphosphate, thus suggesting that the fidelity of the enzymatic reaction is retained.…”

“…The utility of organomercury nucleotides as substrates of polymerases depends strongly on the ligand sphere of Hg II . With relatively weakly coordinating ligands, such as acetato or chlorido, organomercury nucleotides are potent inhibitors of both DNA and RNA polymerases, in all likelihood owing to coordination of Hg II to a critical sulfhydryl group [3,13,14] . In the presence of a thiol ligand, polymerization proceeds smoothly albeit with some concomitant demercuration [15] .…”

“…Enzymatic polymerization of 5‐mercuripyrimidine nucleotides has been proven with both template‐directed [16] as well as template‐independent [13] polymerases. In the former case, 5‐mercuriuridine‐5′‐triphosphate was readily incorporated on a poly[d(AT)] but not on a poly(dG)⋅poly(dC) template while the opposite is true for 5‐mercuricytidine‐5′‐triphosphate, thus suggesting that the fidelity of the enzymatic reaction is retained.…”