eprintid: 1351727
rev_number: 46
eprint_status: archive
userid: 608
dir: disk0/01/35/17/27
datestamp: 2012-07-03 23:21:11
lastmod: 2020-02-13 05:45:02
status_changed: 2012-07-24 09:24:46
type: article
metadata_visibility: show
item_issues_count: 0
creators_name: Davies, RJH
creators_name: Malone, JF
creators_name: Gan, Y
creators_name: Cardin, CJ
creators_name: Lee, MPH
creators_name: Neidle, S
title: High-resolution crystal structure of the intramolecular d(TpA) thymine-adenine photoadduct and its mechanistic implications
ispublished: pub
divisions: UCL
divisions: A01
divisions: B02
divisions: C08
divisions: D10
note: © 2007 The Author(s).

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/2.0/uk/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
abstract: A high-resolution crystal structure is reported for d(TpA)*, the intramolecular thymine–adenine photoadduct that is produced by direct ultraviolet excitation of the dinucleoside monophosphate d(TpA). It confirms the presence of a central 1,3-diazacyclooctatriene ring linking the remnants of the T and A bases, as previously deduced from heteronuclear NMR measurements by Zhao et al. (The structure of d(TpA)*, the major photoproduct of thymidylyl-(3′-5′)-deoxyadenosine. Nucleic Acids Res., 1996, 24, 1554–1560). Within the crystal, the d(TpA)* molecules exist as zwitterions with a protonated amidine fragment of the eight-membered ring neutralizing the charge of the internucleotide phosphate monoanion. The absolute configuration at the original thymine C5 and C6 atoms is determined as 5S,6R. This is consistent with d(TpA)* arising by valence isomerization of a precursor cyclobutane photoproduct with cis–syn stereochemistry that is generated by [2 + 2] photoaddition of the thymine 5,6-double bond across the C6 and C5 positions of adenine. This mode of photoaddition should be favoured by the stacked conformation of adjacent T and A bases in B-form DNA. It is probable that the primary photoreaction is mechanistically analogous to pyrimidine dimerization despite having a much lower quantum yield.
date: 2007-01-30
id_number: PubMed ID: 17264133
official_url: http://dx.doi.org./10.1093/nar/gkl1101
vfaculties: VFLS
oa_status: green
language: eng
primo: open
primo_central: open_green
verified: verified_manual
elements_source: WoS-Lite
elements_id: 418314
doi: 10.1093/nar/gkl1101
lyricists_name: Neidle, Stephen
lyricists_id: SNEID18
full_text_status: public
publication: NUCLEIC ACIDS RESEARCH
volume: 35
number: 4
pagerange: 1048 - 1053
issn: 0305-1048
citation:        Davies, RJH;    Malone, JF;    Gan, Y;    Cardin, CJ;    Lee, MPH;    Neidle, S;      (2007)    High-resolution crystal structure of the intramolecular d(TpA) thymine-adenine photoadduct and its mechanistic implications.                   NUCLEIC ACIDS RESEARCH , 35  (4)   1048 - 1053.    10.1093/nar/gkl1101 <https://doi.org/10.1093/nar%2Fgkl1101>.       Green open access   
 
document_url: https://discovery.ucl.ac.uk/id/eprint/1351727/1/gkl1101.pdf