DNA-REPAIR BY THIOLS IN AIR SHOWS 2 RADICALS MAKE A DOUBLE-STRAND BREAK

被引：41

作者：

MILLIGAN, JR ^{[1
]}

NG, JYY ^{[1
]}

WU, CCL ^{[1
]}

AGUILERA, JA ^{[1
]}

FAHEY, RC ^{[1
]}

WARD, JF ^{[1
]}

机构：

[1] UNIV CALIF SAN DIEGO,DEPT CHEM,LA JOLLA,CA 92093

来源：

RADIATION RESEARCH | 1995年 / 143卷 / 03期

关键词：

D O I：

10.2307/3579213

中图分类号：

Q [生物科学];

学科分类号：

07 ; 0710 ; 09 ;

摘要：

Using agarose gel electrophoresis, we have measured the yields of DNA single- and double-strand breaks (SSBs and DSBs) for plasmid DNA gamma-irradiated in aerobic aqueous solution. The presence during irradiation of either of the thiols cysteamine or N-(2-thioethyl)-1,3-diaminopropane (WR-1O65) resulted in a concentration-dependent decrease in the yield of SSBs and a much greater decrease in the yield of DSBs. This large differential protective effect was not produced by thioethers or an alcohol of structural similarity to the two thiols, suggesting that repair of DSB radical precursors by thiols is more efficient than for SSB precursors. These observations suggest the existence of a diradical intermediate in the formation of DSBs. The results argue against a major contribution by a single radical mechanism involving interstrand radical transfer via hydrogen abstraction by a peroxyl intermediate, since the half-life of this radical transfer reaction appears to be significantly greater than the lifetime of the intermediate. (C) 1995 by Radiation Research Society

引用

页码：273 / 280

页数：8

共 35 条

[1] SALT DEPENDENCE OF OLIGOION POLYION BINDING - A THERMODYNAMIC DESCRIPTION BASED ON PREFERENTIAL INTERACTION COEFFICIENTS [J].