» Articles » PMID: 7708495

Solution Structure of Oligonucleotides Covalently Linked to a Psoralen Derivative

Overview
Specialty Biochemistry
Date 1995 Mar 11
PMID 7708495
Authors
Affiliations
Soon will be listed here.
Abstract

Psoralen (pso) was attached via its C-5 position to the 5'-phosphate group of an oligodeoxynucleotide d(TAAGCCG) by a hexamethylene linker (m6). Complex formation between pso-m6-d(TAAGCCG) and the complementary strands d(CGGCTTA)[7-7mer] or d(CGGCTTAT)[7-8mer] was investigated by nuclear magnetic resonance in aqueous solution. Structural informations derived from DQF-COSY and NOESY maps, revealed that the mini double helix adopts a B-form conformation and that the deoxyriboses preferentially adopt a C2'-endo conformation. The nOe connectivities observed between the protons of the bases or the sugars in each duplex, and the protons of the psoralen and the hexamethylene chain, led us to propose a model involving an equilibrium between two conformations due to different locations of the psoralen. Upon UV-irradiation, the psoralen moiety cross-linked the two DNA strands at the level of 5'TpA3' sequences. NMR studies of the single major photo-cross-linked duplex pso-m6-d(TAAGCCG) and d(CGGCTTA) were performed. The stereochemistry of the diadduct is indeed cis-syn at both cyclobutane rings. In addition, the effects of this diadduct on the helical structure are analyzed in detail.

References
1.
PULLMAN B, Borer P, Kan L, Tso P . Ring-current effects in the Nmr of nucleic acids: a graphical approach. Biopolymers. 1976; 15(11):2277-86. DOI: 10.1002/bip.1976.360151114. View

2.
Gincel E, Lancelot G, Maurizot J, Thuong N, Vovelle F . Comparison of solution structure of free and complexed lac operator by molecular modelling with NMR constraints. Biochimie. 1994; 76(2):141-51. DOI: 10.1016/0300-9084(94)90006-x. View

3.
Peckler S, Graves B, Kanne D, Rapoport H, Hearst J, Kim S . Structure of a psoralen-thymine monoadduct formed in photoreaction with DNA. J Mol Biol. 1982; 162(1):157-72. DOI: 10.1016/0022-2836(82)90166-8. View

4.
Marion D, Wuthrich K . Application of phase sensitive two-dimensional correlated spectroscopy (COSY) for measurements of 1H-1H spin-spin coupling constants in proteins. Biochem Biophys Res Commun. 1983; 113(3):967-74. DOI: 10.1016/0006-291x(83)91093-8. View

5.
Hare D, Wemmer D, Chou S, Drobny G, Reid B . Assignment of the non-exchangeable proton resonances of d(C-G-C-G-A-A-T-T-C-G-C-G) using two-dimensional nuclear magnetic resonance methods. J Mol Biol. 1983; 171(3):319-36. DOI: 10.1016/0022-2836(83)90096-7. View