Position-specific trapping of topoisomerase II by benzo[a]pyrene diol epoxide adducts: implications for interactions with intercalating anticancer agents.

نویسندگان

  • Qasim A Khan
  • Glenda Kohlhagen
  • Richard Marshall
  • Caroline A Austin
  • Govind P Kalena
  • Heiko Kroth
  • Jane M Sayer
  • Donald M Jerina
  • Yves Pommier
چکیده

DNA topoisomerase II (Top2) is the target of some of the most effective anticancer DNA intercalators. To determine the effect of intercalating ligands at defined positions relative to a known DNA cleavage site for human Top2alpha, we synthesized oligodeoxynucleotides containing single trans-opened benzo[a]pyrene 7,8-diol 9,10-epoxide (DE) deoxyadenosine (dA) adducts of known absolute configuration, placed at specific positions in a duplex sequence containing staggered Top2 cleavage sites on both strands. Because the orientations of the intercalated hydrocarbon are known from NMR solution structures of duplex oligonucleotides containing these dA adducts, a detailed analysis of the relationship between the position of intercalation and trapping of Top2 is possible. Our findings demonstrate that (i) Top2 cleavage complexes are trapped by intercalation of the hydrocarbon at either of the staggered cleavage sites or immediately adjacent to the base pairs flanking the cleavage sites within the stagger; (ii) both concerted and nonconcerted cleavage by both subunits of a Top2 homodimer were detected depending on the position of the benzo[a]pyrene DE dA adduct; and (iii) intercalation immediately outside of the staggered Top2 cleavage site, and to a lesser extent in the middle of the stagger, prevents Top2 from cleaving DNA at this site, consistent with the effect of some intercalators as suppressors of Top2-mediated DNA cleavage. These results identify specific binding sites for intercalators that result in trapping of Top2. Such poisoning of Top2 by bulky polycyclic aromatic hydrocarbon DE adducts constitutes a potential mechanism for their carcinogenic activity.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Position-specific trapping of topoisomerase I-DNA cleavage complexes by intercalated benzo[a]- pyrene diol epoxide adducts at the 6-amino group of adenine.

DNA topoisomerase I (top1) is the target of potent anticancer agents, including camptothecins and DNA intercalators, which reversibly stabilize (trap) top1 catalytic intermediates (cleavage complexes). The aim of the present study was to define the structural relationship between the site(s) of covalently bound intercalating agents, whose solution conformations in DNA are known, and the site(s)...

متن کامل

An Improved Fluorometric Assay for Dosimetry of Benzo(a)pyrene Diol-Epoxide-DNA Adducts in Smokers' Lung: Comparisons with Total Bulky Adducts and Aryl Hydrocarbon Hydroxylase Activity1

An improved high-performance liquid chromatography/fluorometric assay has been established to quantitate the benzo(«)pyrene (BP) tetrols released after acid hydrolysis of lung DN A from lung cancer patients, so that the formation of benzo(a)pyrene diol-epoxide-DNA adducts can be measured. The r-7,c-10,f-8,f-9-tetrahydroxy-7,8,9,10-tetrahydro-BP isolated by high-performance liquid chromatograph...

متن کامل

Hydroxylase Activity Comparisons with Total Bulky Adducts and Aryl Hydrocarbon )pyrene Diol-Epoxide-DNA Adducts in Smokers' Lung: a An Improved Fluorometric Assay for Dosimetry of Benzo(

An improved high-performance liquid chromatography/fluorometric assay has been established to quantitate the benzo(«)pyrene (BP) tetrols released after acid hydrolysis of lung DN A from lung cancer patients, so that the formation of benzo(a)pyrene diol-epoxide-DNA adducts can be measured. The r-7,c-10,f-8,f-9-tetrahydroxy-7,8,9,10-tetrahydro-BP isolated by high-performance liquid chromatograph...

متن کامل

An improved fluorometric assay for dosimetry of benzo(a)pyrene diol-epoxide-DNA adducts in smokers' lung: comparisons with total bulky adducts and aryl hydrocarbon hydroxylase activity.

An improved high-performance liquid chromatography/fluorometric assay has been established to quantitate the benzo(a)pyrene (BP) tetrols released after acid hydrolysis of lung DNA from lung cancer patients, so that the formation of benzo(a)pyrene diol-epoxide-DNA adducts can be measured. The r-7,c-10,t-8,t-9-tetrahydroxy-7,8,9,10-tetrahydro-BP isolated by high-performance liquid chromatography ...

متن کامل

Benzo[a]pyrene-dG adduct interference illuminates the interface of vaccinia topoisomerase with the DNA minor groove.

Vaccinia DNA topoisomerase forms a covalent DNA-(3'-phosphotyrosyl)-enzyme intermediate at a pentapyrimidine target site 5'-C(+5)C(+4)C(+3)T(+2)T(+1)p downward arrow in duplex DNA. The enzyme engages the target site within a C-shaped protein clamp. Here we mapped the interface of topoisomerase with the DNA minor groove by introducing chiral C-10 R and S 7,8-diol 9,10-epoxide adducts of benzo[a]...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • Proceedings of the National Academy of Sciences of the United States of America

دوره 100 21  شماره 

صفحات  -

تاریخ انتشار 2003