INTERSTRAND CROSS-LINKING OF DUPLEX DNA BY NITROUS-ACID - COVALENT STRUCTURE OF THE DG-TO-DG CROSS-LINK AT THE SEQUENCE 5'-CG

被引:83
作者
KIRCHNER, JJ [1 ]
SIGURDSSON, ST [1 ]
HOPKINS, PB [1 ]
机构
[1] UNIV WASHINGTON, DEPT CHEM, SEATTLE, WA 98195 USA
关键词
D O I
10.1021/ja00037a001
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
It has previously been shown in synthetic oligodeoxynucleotides that the interstrand cross-linking reaction of nitrous acid with duplex DNA preferentially forms thermally- and base-stable links between deoxyguanosine residues at the duplex sequence 5'-CG. The covalent nucleus of this linkage is shown herein to result from the presence of a residue in which the original deoxyguanosyl residues on opposite strands are cross-linked through a single N2 atom common to both [N2-(2-deoxyinosyl)deoxyguanosine residue]. Variation of nitrous acid concentration, reaction time, and temperature established conditions under which up to a several percent yield of cross-linked oligodeoxynucleotide was obtained. Evidence for the covalent structure of the cross-link reported herein includes comparison of spectroscopic properties (mass spectrum, ultraviolet spectra at three pH values, and H-1 NMR spectrum) of N-(2-deoxyinosyl)deoxyguanosine isolated by enzymatic hydrolysis of cross-linked oligodeoxynucleotides to those of the same substance and its derivatives previously isolated from nitrous acid-treated calf thymus DNA. Further evidence in favor of cross-linking through N2 is reported: substitution of deoxyinosine, which lacks an N2 amino group, in place of deoxyguanosine at both sites in the duplex sequence 5'-CG abolishes dG-to-dG (dI-to-dI) cross-linking.
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页码:4021 / 4027
页数:7
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