Deoxyribonucleic acids cleavage

Deoxyribonucleic acid footprinting studies have shown that HMG domains A and B inhibit cleavage by nucleases over a 12- to 15-base-pair region centered around the platinum adduct (81). The HMG proteins can modulate cisplatin cytotoxicity by inhibition of the excinuclease-mediated removal of Pt-d(GpG) adducts from DNA (82). However, this hypothesis has been questioned because there is no evidence for cellular protein shielding of Pt-d(GpG) adducts from repair enzymes (83). 

This zinc-dependent endonuclease [EC 3.1.30.1] can act on either ribo- or deoxyribonucleic acids, with a preference for single-stranded substrates. It catalyzes the endonucleolytic cleavage of those nucleic acids to 5 -phospho-mononucleotide and 5 -phosphooligonucleotide end-products. 

The attachment of zinc to the phosphate groups and the subsequent cleavage of the phosphate bonds demonstrate the case opposite to Dr. Jones , in that metal ions are much more effective than protons in this cleavage reaction. Evidently this is caused by stabilization of the intermediate by chelation of the metal to the hydroxyl group as well as to the phosphate. In fact, deoxyribonucleic acid (DNA), which is like RNA except that it lacks the 2 -hydroxyl group, cannot be cleaved by metal ions. 

The pathway by which the 3, 5 -diphosphate esters of thymidine and 2 -deoxycytidine are formed during acid hydrolysis of 2 -deoxyribonucleic acid is shown in Scheme 27 " Cleavage of the glycosylic linkages to the... 

Marshall LE, Graham DR, Reich KA, Sigman DS. Cleavage of deoxyribonucleic acid by the l,10-phenanthrohne-cuprous complex. Hydrogen peroxide requirement and primary and secondary structure specificity. Biochemistry. 1981 20 244-250. 

Cleavage o Purines and Pyrimidines from Deoxyribonucleic Acids according to Yischer and Chargaff and to Wyatt [99,105]... 

Cleavage of Purines and Pyrimidines from Ribo- and Deoxyribonucleic Acids according to Marshak and Vogel [46,105]... 

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