Generation of guanine-amino acid cross-links by a free radical combination mechanism

Yuriy Uvaydov, Nicholas Geacintov, Vladimir Shafirovich

Research output: Contribution to journalArticle

Abstract

A direct method has been developed for the in vitro synthesis of stable DNA-protein cross-links (DPC's) between guanine and amino acids (lysine and arginine). This method employs the combination of guanine neutral radicals, G(-H), and side-chain C-centered amino acid radicals. The latter were generated indirectly after first causing the selective photoionization of 2-aminopurine (2AP) embedded in the oligonucleotide, 5′-d(CC[2AP]TCGCTACC), by intense nanosecond 308 nm excimer laser pulses. The 2AP radical cation deprotonates rapidly to form the 2AP(-H) neutral radical which, in turn, oxidizes the nearby guanine to form the neutral guanine G(-H) radical, as described previously (Shafirovich et al., J. Phys. Chem. B, 2001, 105, 8431). In parallel, the hydrated electrons, generated by the photoionization of 2AP, are scavenged by nitrous oxide to generate hydroxyl radicals. In the presence of a large excess of the amino acids, the hydroxyl radicals oxidize the latter to produce C-centered amino acid radicals that combine with the G(-H) radicals to form the guanine-amino acid cross-linked oligonucleotide product. Analogous products were generated by photoionizing the free nucleoside, 2′,3′,5′-tri- O-acetylguanosine, (tri-O-Ac-Guo), using intense nanosecond 266 nm Nd:YAG laser pulse irradiation. The guanine-amino acid cross-links thus produced site-specifically positioned either in oligonucleotides, or in the free nucleoside tri-O-Ac-Guo were isolated by HPLC methods and identified by high resolution LC-TOF/MS and LC-MS/MS methods. The possibility that analogous guanine-amino acid cross-linked products could be formed in vivo using single hit radical generation mechanisms during oxidative stress is discussed.

Original languageEnglish (US)
Pages (from-to)11729-11736
Number of pages8
JournalPhysical Chemistry Chemical Physics
Volume16
Issue number23
DOIs
StatePublished - Jun 21 2014

Fingerprint

guanines
Guanine
2-Aminopurine
free radicals
Free Radicals
amino acids
Amino Acids
oligonucleotides
Oligonucleotides
Photoionization
nucleosides
Nucleosides
hydroxyl radicals
Hydroxyl Radical
Laser pulses
photoionization
products
Excimer Lasers
Oxidative stress
Solid-State Lasers

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Physics and Astronomy(all)
  • Medicine(all)

Cite this

Generation of guanine-amino acid cross-links by a free radical combination mechanism. / Uvaydov, Yuriy; Geacintov, Nicholas; Shafirovich, Vladimir.

In: Physical Chemistry Chemical Physics, Vol. 16, No. 23, 21.06.2014, p. 11729-11736.

Research output: Contribution to journalArticle

@article{ce5e863fde1a42b9a709bb5d13522bd1,
title = "Generation of guanine-amino acid cross-links by a free radical combination mechanism",
abstract = "A direct method has been developed for the in vitro synthesis of stable DNA-protein cross-links (DPC's) between guanine and amino acids (lysine and arginine). This method employs the combination of guanine neutral radicals, G(-H), and side-chain C-centered amino acid radicals. The latter were generated indirectly after first causing the selective photoionization of 2-aminopurine (2AP) embedded in the oligonucleotide, 5′-d(CC[2AP]TCGCTACC), by intense nanosecond 308 nm excimer laser pulses. The 2AP radical cation deprotonates rapidly to form the 2AP(-H) neutral radical which, in turn, oxidizes the nearby guanine to form the neutral guanine G(-H) radical, as described previously (Shafirovich et al., J. Phys. Chem. B, 2001, 105, 8431). In parallel, the hydrated electrons, generated by the photoionization of 2AP, are scavenged by nitrous oxide to generate hydroxyl radicals. In the presence of a large excess of the amino acids, the hydroxyl radicals oxidize the latter to produce C-centered amino acid radicals that combine with the G(-H) radicals to form the guanine-amino acid cross-linked oligonucleotide product. Analogous products were generated by photoionizing the free nucleoside, 2′,3′,5′-tri- O-acetylguanosine, (tri-O-Ac-Guo), using intense nanosecond 266 nm Nd:YAG laser pulse irradiation. The guanine-amino acid cross-links thus produced site-specifically positioned either in oligonucleotides, or in the free nucleoside tri-O-Ac-Guo were isolated by HPLC methods and identified by high resolution LC-TOF/MS and LC-MS/MS methods. The possibility that analogous guanine-amino acid cross-linked products could be formed in vivo using single hit radical generation mechanisms during oxidative stress is discussed.",
author = "Yuriy Uvaydov and Nicholas Geacintov and Vladimir Shafirovich",
year = "2014",
month = "6",
day = "21",
doi = "10.1039/c4cp00675e",
language = "English (US)",
volume = "16",
pages = "11729--11736",
journal = "Physical Chemistry Chemical Physics",
issn = "1463-9076",
publisher = "Royal Society of Chemistry",
number = "23",

}

TY - JOUR

T1 - Generation of guanine-amino acid cross-links by a free radical combination mechanism

AU - Uvaydov, Yuriy

AU - Geacintov, Nicholas

AU - Shafirovich, Vladimir

PY - 2014/6/21

Y1 - 2014/6/21

N2 - A direct method has been developed for the in vitro synthesis of stable DNA-protein cross-links (DPC's) between guanine and amino acids (lysine and arginine). This method employs the combination of guanine neutral radicals, G(-H), and side-chain C-centered amino acid radicals. The latter were generated indirectly after first causing the selective photoionization of 2-aminopurine (2AP) embedded in the oligonucleotide, 5′-d(CC[2AP]TCGCTACC), by intense nanosecond 308 nm excimer laser pulses. The 2AP radical cation deprotonates rapidly to form the 2AP(-H) neutral radical which, in turn, oxidizes the nearby guanine to form the neutral guanine G(-H) radical, as described previously (Shafirovich et al., J. Phys. Chem. B, 2001, 105, 8431). In parallel, the hydrated electrons, generated by the photoionization of 2AP, are scavenged by nitrous oxide to generate hydroxyl radicals. In the presence of a large excess of the amino acids, the hydroxyl radicals oxidize the latter to produce C-centered amino acid radicals that combine with the G(-H) radicals to form the guanine-amino acid cross-linked oligonucleotide product. Analogous products were generated by photoionizing the free nucleoside, 2′,3′,5′-tri- O-acetylguanosine, (tri-O-Ac-Guo), using intense nanosecond 266 nm Nd:YAG laser pulse irradiation. The guanine-amino acid cross-links thus produced site-specifically positioned either in oligonucleotides, or in the free nucleoside tri-O-Ac-Guo were isolated by HPLC methods and identified by high resolution LC-TOF/MS and LC-MS/MS methods. The possibility that analogous guanine-amino acid cross-linked products could be formed in vivo using single hit radical generation mechanisms during oxidative stress is discussed.

AB - A direct method has been developed for the in vitro synthesis of stable DNA-protein cross-links (DPC's) between guanine and amino acids (lysine and arginine). This method employs the combination of guanine neutral radicals, G(-H), and side-chain C-centered amino acid radicals. The latter were generated indirectly after first causing the selective photoionization of 2-aminopurine (2AP) embedded in the oligonucleotide, 5′-d(CC[2AP]TCGCTACC), by intense nanosecond 308 nm excimer laser pulses. The 2AP radical cation deprotonates rapidly to form the 2AP(-H) neutral radical which, in turn, oxidizes the nearby guanine to form the neutral guanine G(-H) radical, as described previously (Shafirovich et al., J. Phys. Chem. B, 2001, 105, 8431). In parallel, the hydrated electrons, generated by the photoionization of 2AP, are scavenged by nitrous oxide to generate hydroxyl radicals. In the presence of a large excess of the amino acids, the hydroxyl radicals oxidize the latter to produce C-centered amino acid radicals that combine with the G(-H) radicals to form the guanine-amino acid cross-linked oligonucleotide product. Analogous products were generated by photoionizing the free nucleoside, 2′,3′,5′-tri- O-acetylguanosine, (tri-O-Ac-Guo), using intense nanosecond 266 nm Nd:YAG laser pulse irradiation. The guanine-amino acid cross-links thus produced site-specifically positioned either in oligonucleotides, or in the free nucleoside tri-O-Ac-Guo were isolated by HPLC methods and identified by high resolution LC-TOF/MS and LC-MS/MS methods. The possibility that analogous guanine-amino acid cross-linked products could be formed in vivo using single hit radical generation mechanisms during oxidative stress is discussed.

UR - http://www.scopus.com/inward/record.url?scp=84901247323&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84901247323&partnerID=8YFLogxK

U2 - 10.1039/c4cp00675e

DO - 10.1039/c4cp00675e

M3 - Article

C2 - 24810398

AN - SCOPUS:84901247323

VL - 16

SP - 11729

EP - 11736

JO - Physical Chemistry Chemical Physics

JF - Physical Chemistry Chemical Physics

SN - 1463-9076

IS - 23

ER -