Abstract: A method of inhibiting at least one molecular process in a sample, comprising administering to the sample an oligonucleotide or polynucleotide containing at least one monomeric unit having formula (I): A—Xn  (I) wherein A is an organic moiety, n is at least 1, and each X is independently selected from the group consisting of —NRCOCONu, —NHCOCR2CR2CONu, —NHCOCR═CRCONu, and —NHCOSSCONu, wherein each R independently represents H or a substituted or unsubstituted alkyl group, and Nu represents a nucleophile, or a salt of the compound.

Abstract: A type 1 topoisomerase, designated topoisomerase V, has been isolated and substantially purified from the halophilic thermophilic methanogen bacterium Methanopyrus kandleri. The topoisomerase was purified by a process including the steps of lysing cells of M. kandleri to form a lysate, treating the lysate with polyethyleneimine to form a precipitate and a supernatant, precipitating the polyethyleneimine supernatant with ammonium sulfate, chromatographing the ammonium sulfate precipitate on phosphocellulose to produce a phosphocellulose eluate, chromatographing the phosphocellulose eluate on heparin to produce a heparin eluate, and chromatographing the heparin eluate on a column capable separating proteins by molecular size therein to produce a substantially purified thermostable DNA topoisomerase V. Topoisomerase V can relax DNA and can unlink DNA by reducing the linking number of closed circular DNA.

Abstract: A type 1 topoisomerase, designated topoisomerase V, has been isolated and substantially purified from the halophilic thermophilic methanogen bacterium Methanopyrus kandleri. The topoisomerase was purified by a process including the steps of lysing cells of M. kandleri to form a lysate, treating the lysate with polyethyleneimine to form a precipitate and a supernatant, precipitating the polyethyleneimine supernatant with ammonium sulfate, chromatographing the ammonium sulfate precipitate on phosphocellulose to produce a phosphocellulose eluate, chromatographing the phosphocellulose eluate on heparin to produce a heparin eluate, and chromatographing the heparin eluate on a column capable of separating proteins by molecular size therein to produce a substantially purified thermostable DNA topoisomerase V. Topoisomerase V can relax DNA and can unlink DNA by reducing the linking number of closed circular DNA.