title: Covalently bound ribonucleotides in crab d(A-T) polymer.
abstract: In addition to the known 3% of G + C residues, samples of purified crab d(A-T) polymer from Cancer borealis contained small amounts (< 3%) of RNA. Aliquots of d(A-T)n were digested with crude venom, and the resultant nucleosides were analyzed by high pressure liquid chromatography (HPLC); up to one-half of all guanosine was rG. Other aliquots were exhaustively digested with purified pancreatic DNase I to produce 88% dinucleotides. HPLC fractionation of this dinucleotide mixture into individual components revealed the presence of three mixed dinucleotides: -dC-rG, -dT-rA, and -dT-rG. A third aliquot of d(A-T)n was hydrolyzed overnight with 0.3 M KOH at 37 degrees C; approximately equal amounts of ribomononucleotides (predominantly containing purines) and deoxyribomononucleotides (predominantely containg thymine) were produced. KOH-hydrolyzable ribonucleotides accounted for one-third to one-half of the total RNA. The rest of the ribonucleotides remained with longer d-fragments, presumably as 3'(2')-terminal nucleotides (. . .d-d-d-rp). It was concluded that crab d(A-T) polymer from C. borealis contains 1 to 3% of dispersed, covalently bound ribonucleotides. The results also suggest that the sugar specificity of DNase I may be limited to a nucleotide following the cleavage.
mesh_terms: D000469:Alkaline Phosphatase; D000818:Animals; D003386:Brachyura; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D004247:DNA / Q000032:analysis; D003851:Deoxyribonucleases; D003854:Deoxyribonucleotides / Q000032:analysis*; D008297:Male; D010179:Pancreas / Q000201:enzymology; D011067:Poly dA-dT; D011089:Polydeoxyribonucleotides; D013737:Testis / Q000032:analysis*
chemical_list: D003854:Deoxyribonucleotides; D011089:Polydeoxyribonucleotides; D011067:Poly dA-dT; D004247:DNA; D003851:Deoxyribonucleases; D000469:Alkaline Phosphatase