193 NM LIGHT INDUCES SINGLE-STRAND BREAKAGE OF DNA PREDOMINANTLY AT GUANINE

被引:88
作者
MELVIN, T
PLUMB, MA
BOTCHWAY, SW
ONEILL, P
PARKER, AW
机构
[1] MRC,RADIOBIOL UNIT,DIDCOT OX11 0RD,OXON,ENGLAND
[2] RUTHERFORD APPLETON LAB,CENT LASER FACIL,DIDCOT OX11 0QX,OXON,ENGLAND
关键词
D O I
10.1111/j.1751-1097.1995.tb09873.x
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Irradiation of DNA with 193 nm light results in monophotonic photoionization, with the formation of a base radical cation and a hydrated electron (phi(P1) = 0.048-0.065). Although >50% Of the photoionization events initially occur at guanine in DNA, migration of the ''hole'' from the other bases to guanine occurs to yield predominantly its radical cation or its deprotonated form. From sequence analysis, the data reveal that 193 nm light induces single strand breaks (ssb) in double-stranded DNA preferential 3' to a guanine residue. However, it has previously been reported that 193 nm light yields very low yields of ssb (<2% of the yield of e(-)aq). The distribution of these ssb at guanine is nonrandom, showing a dependence on the neighboring base moiety, The efficiency of ssb formation at nonguanine sites is estimated to be at least one order of magnitude lower. The preferred cleavage at guanine is consistent with migration and localization of the electron loss center at guanine. It is argued that singlet oxygen and the photoionized phosphate group of the sugar moiety are not major precursors to ssb. At present, the mechanisms of strand breakage are not known although a guanine radical or one of its products remain potential precursors.
引用
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页码:584 / 591
页数:8
相关论文
共 46 条
[1]  
BECKER D, 1993, ADV RADIAT BIOL, V17, P121
[2]   COMBINATION IS THE DOMINANT FREE-RADICAL PROCESS INITIATED IN DNA BY IONIZING-RADIATION - AN OVERVIEW BASED ON SOLID-STATE EPR STUDIES [J].
BERNHARD, WA ;
MROCZKA, N ;
BARNES, J .
INTERNATIONAL JOURNAL OF RADIATION BIOLOGY, 1994, 66 (05) :491-497
[3]  
BERNHARD WA, 1981, ADV RADIAT BIOL, V9, P199, DOI DOI 10.1016/B978-0-12-035409-2.50011-4
[4]   RE-EVALUATION OF SPECTRAL AND KINETIC-PROPERTIES OF HO2 AND (0--)2 FREE-RADICALS [J].
BIELSKI, BHJ .
PHOTOCHEMISTRY AND PHOTOBIOLOGY, 1978, 28 (4-5) :645-649
[5]   SINGLET OXYGEN SENSITIZATION BY EXCITED-STATE DNA [J].
BISHOP, SM ;
MALONE, M ;
PHILLIPS, D ;
PARKER, AW ;
SYMONS, MCR .
JOURNAL OF THE CHEMICAL SOCIETY-CHEMICAL COMMUNICATIONS, 1994, (07) :871-872
[7]   EFFECTS OF IONIZING-RADIATION ON DEOXYRIBONUCLEIC-ACID AND RELATED SYSTEMS .1. THE ROLE OF OXYGEN [J].
BOON, PJ ;
CULLIS, PM ;
SYMONS, MCR ;
WREN, BW .
JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 2, 1984, (08) :1393-1399
[8]   CRITICAL-REVIEW OF RATE CONSTANTS FOR REACTIONS OF HYDRATED ELECTRONS, HYDROGEN-ATOMS AND HYDROXYL RADICALS (.OH/.O-) IN AQUEOUS-SOLUTION [J].
BUXTON, GV ;
GREENSTOCK, CL ;
HELMAN, WP ;
ROSS, AB .
JOURNAL OF PHYSICAL AND CHEMICAL REFERENCE DATA, 1988, 17 (02) :513-886
[9]   ELECTRON-TRANSFER IN DI(DEOXY)NUCLEOSIDE PHOSPHATES IN AQUEOUS-SOLUTION - RAPID MIGRATION OF OXIDATIVE DAMAGE (VIA ADENINE) TO GUANINE [J].
CANDEIAS, LP ;
STEENKEN, S .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1993, 115 (06) :2437-2440
[10]   IONIZATION OF POLYNUCLEOTIDES AND DNA IN AQUEOUS-SOLUTION BY 193 NM PULSED LASER-LIGHT - IDENTIFICATION OF BASE-DERIVED RADICALS [J].
CANDEIAS, LP ;
ONEILL, P ;
JONES, GDD ;
STEENKEN, S .
INTERNATIONAL JOURNAL OF RADIATION BIOLOGY, 1992, 61 (01) :15-20