Matches in SemOpenAlex for { <https://semopenalex.org/work/W2017983775> ?p ?o ?g. }
- W2017983775 endingPage "607" @default.
- W2017983775 startingPage "593" @default.
- W2017983775 abstract "Telomere shortening occurs during oxidative and inflammatory stress with guanine (G) as the major site of damage. In this work, a comprehensive profile of the sites of oxidation and structures of products observed from G-quadruplex and duplex structures of the human telomere sequence was studied in the G-quadruplex folds (hybrid (K(+)), basket (Na(+)), and propeller (K(+) + 50% CH3CN)) resulting from the sequence 5'-(TAGGGT)4T-3' and in an appropriate duplex containing one telomere repeat. Oxidations with four oxidant systems consisting of riboflavin photosensitization, carbonate radical generation, singlet oxygen, and the copper Fenton-like reaction were analyzed under conditions of low product conversion to determine relative reactivity. The one-electron oxidants damaged the 5'-G in G-quadruplexes leading to spiroiminodihydantoin (Sp) and 2,2,4-triamino-2H-oxazol-5-one (Z) as major products as well as 8-oxo-7,8-dihydroguanine (OG) and 5-guanidinohydantoin (Gh) in low relative yields, while oxidation in the duplex context produced damage at the 5'- and middle-Gs of GGG sequences and resulted in Gh being the major product. Addition of the reductant N-acetylcysteine (NAC) to the reaction did not alter the riboflavin-mediated damage sites but decreased Z by 2-fold and increased OG by 5-fold, while not altering the hydantoin ratio. However, NAC completely quenched the CO3(•-) reactions. Singlet oxygen oxidations of the G-quadruplex showed reactivity at all Gs on the exterior faces of G-quartets and furnished the product Sp, while no oxidation was observed in the duplex context under these conditions, and addition of NAC had no effect. Because a long telomere sequence would have higher-order structures of G-quadruplexes, studies were also conducted with 5'-(TAGGGT)8-T-3', and it provided oxidation profiles similar to those of the single G-quadruplex. Lastly, Cu(II)/H2O2-mediated oxidations were found to be indiscriminate in the damage patterns, and 5-carboxamido-5-formamido-2-iminohydantoin (2Ih) was found to be a major duplex product, while nearly equal yields of 2Ih and Sp were observed in G-quadruplex contexts. These findings indicate that the nature of the secondary structure of folded DNA greatly alters both the reactivity of G toward oxidative stress as well as the product outcome and suggest that recognition of damage in telomeric sequences by repair enzymes may be profoundly different from that of B-form duplex DNA." @default.
- W2017983775 created "2016-06-24" @default.
- W2017983775 creator A5003239051 @default.
- W2017983775 creator A5005659666 @default.
- W2017983775 date "2013-03-13" @default.
- W2017983775 modified "2023-10-02" @default.
- W2017983775 title "G-Quadruplex Folds of the Human Telomere Sequence Alter the Site Reactivity and Reaction Pathway of Guanine Oxidation Compared to Duplex DNA" @default.
- W2017983775 cites W1487243507 @default.
- W2017983775 cites W1965058583 @default.
- W2017983775 cites W1968969258 @default.
- W2017983775 cites W1972972944 @default.
- W2017983775 cites W1973428256 @default.
- W2017983775 cites W1975485903 @default.
- W2017983775 cites W1976706105 @default.
- W2017983775 cites W1978638462 @default.
- W2017983775 cites W1978937208 @default.
- W2017983775 cites W1979946638 @default.
- W2017983775 cites W1981912201 @default.
- W2017983775 cites W1984941212 @default.
- W2017983775 cites W1986216535 @default.
- W2017983775 cites W1991615875 @default.
- W2017983775 cites W1991742118 @default.
- W2017983775 cites W1991952977 @default.
- W2017983775 cites W1992595091 @default.
- W2017983775 cites W1993571663 @default.
- W2017983775 cites W1994748126 @default.
- W2017983775 cites W1995943720 @default.
- W2017983775 cites W1996368650 @default.
- W2017983775 cites W1998085469 @default.
- W2017983775 cites W1998808749 @default.
- W2017983775 cites W1999897229 @default.
- W2017983775 cites W2000774559 @default.
- W2017983775 cites W2000929500 @default.
- W2017983775 cites W2002675613 @default.
- W2017983775 cites W2004291475 @default.
- W2017983775 cites W2005921112 @default.
- W2017983775 cites W2006878559 @default.
- W2017983775 cites W2007812774 @default.
- W2017983775 cites W2008120871 @default.
- W2017983775 cites W2010738299 @default.
- W2017983775 cites W2010844179 @default.
- W2017983775 cites W2010882280 @default.
- W2017983775 cites W2012219231 @default.
- W2017983775 cites W2015240507 @default.
- W2017983775 cites W2015746380 @default.
- W2017983775 cites W2015874842 @default.
- W2017983775 cites W2016729820 @default.
- W2017983775 cites W2016904635 @default.
- W2017983775 cites W2018446508 @default.
- W2017983775 cites W2019986419 @default.
- W2017983775 cites W2026838497 @default.
- W2017983775 cites W2027537858 @default.
- W2017983775 cites W2029257212 @default.
- W2017983775 cites W2031454321 @default.
- W2017983775 cites W2034484350 @default.
- W2017983775 cites W2035253002 @default.
- W2017983775 cites W2037291224 @default.
- W2017983775 cites W2038929178 @default.
- W2017983775 cites W2039228013 @default.
- W2017983775 cites W2040843368 @default.
- W2017983775 cites W2041107514 @default.
- W2017983775 cites W2041579368 @default.
- W2017983775 cites W2041834340 @default.
- W2017983775 cites W2043021911 @default.
- W2017983775 cites W2043841668 @default.
- W2017983775 cites W2044723896 @default.
- W2017983775 cites W2045629535 @default.
- W2017983775 cites W2045910186 @default.
- W2017983775 cites W2050224588 @default.
- W2017983775 cites W2050433250 @default.
- W2017983775 cites W2051865375 @default.
- W2017983775 cites W2053861316 @default.
- W2017983775 cites W2055989196 @default.
- W2017983775 cites W2058044047 @default.
- W2017983775 cites W2058647905 @default.
- W2017983775 cites W2058659691 @default.
- W2017983775 cites W2059540845 @default.
- W2017983775 cites W2060886270 @default.
- W2017983775 cites W2060912121 @default.
- W2017983775 cites W2061224795 @default.
- W2017983775 cites W2061625987 @default.
- W2017983775 cites W2061764665 @default.
- W2017983775 cites W2062420358 @default.
- W2017983775 cites W2062724831 @default.
- W2017983775 cites W2066439157 @default.
- W2017983775 cites W2069297991 @default.
- W2017983775 cites W2072258154 @default.
- W2017983775 cites W2073772824 @default.
- W2017983775 cites W2073841855 @default.
- W2017983775 cites W2075638681 @default.
- W2017983775 cites W2076608851 @default.
- W2017983775 cites W2077450957 @default.
- W2017983775 cites W2077891056 @default.
- W2017983775 cites W2078843953 @default.
- W2017983775 cites W2079352625 @default.
- W2017983775 cites W2081963503 @default.
- W2017983775 cites W2082060238 @default.
- W2017983775 cites W2083099355 @default.