Synthesis, characterization, and crystal structures of M(DO3A) (M = iron, gadolinium) and Na[M(DOTA)] (M = Fe, yttrium, Gd)

Chang, C. Allen; Francesconi, Lynn C.; Malley, Mary F.; Kumar, Krishan; Gougoutas, Jack Z.; Tweedle, Michael F.; Lee, D. W.; Wilson, L. J.

doi:10.1021/ic00068a020

Cited by 269 publications

(217 citation statements)

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“…This paper investigates the application of selective relaxation agents to maintain a large water polarization, and a formalism describing the propagation of water polarization during the course of different NMR experiments is presented and experimentally validated. The increase of the signal intensity in very large macromolecular solutes by adding a suitable concentration of the relaxation agent Gd(DOTA) (Chang et al, 1993) is demonstrated with the 800 kDa chaperonin GroEL (Xu et al, 1997). We further propose that experiments for studies of solutes with molecular weights larger than about 30 kDa, which would normally be recorded with water flip-back pulses, can in the presence of suitably selected relaxation enhancement reagents be performed with comparable sensitivity using saturation of the water resonance.…”

Section: Introductionmentioning

confidence: 89%

“…Taking Gd(DOTA) ) (Chang et al, 1993) as an example, which is a typical relaxation agent used in magnetic resonance imaging (MRI), eight of the nine coordination sites of the gadolinium ion are occupied by the chelating molecule DOTA 4) . One water molecule at a time can bind to the remaining ninth coordination site, where it can approach close to the gadolinium ion.…”

Section: Propagation Of the Water Polarizationmentioning

confidence: 99%

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Managing the solvent water polarization to obtain improved NMR spectra of large molecular structures

et al. 2005

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In large molecular structures, the magnetization of all hydrogen atoms in the solute is strongly coupled to the water magnetization through chemical exchange between solvent water and labile protons of macromolecular components, and through dipole-dipole interactions and the associated ''spin diffusion'' due to slow molecular tumbling. In NMR experiments with such systems, the extent of the water polarization is thus of utmost importance. This paper presents a formalism that describes the propagation of the water polarization during the course of different NMR experiments, and then compares the results of model calculations for optimized water polarization with experimental data. It thus demonstrates that NMR spectra of large molecular structures can be improved with the use of paramagnetic spin relaxation agents which selectively enhance the relaxation of water protons, so that a substantial gain in signal-to-noise can be achieved. The presently proposed use of a relaxation agent can also replace the water flip-back pulses when working with structures larger than about 30 kDa. This may be a valid alternative in situations where flip-back pulses are difficult to introduce into the overall experimental scheme, or where they would interfere with other requirements of the NMR experiment.

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Section: Introductionmentioning

confidence: 89%

Section: Propagation Of the Water Polarizationmentioning

confidence: 99%

Managing the solvent water polarization to obtain improved NMR spectra of large molecular structures

et al. 2005

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“…Isso pôde ser feito através do banco de dados de estruturas cristalográficas CCSD, 17 onde o código CCSD para o referido complexo é o JOPJIH01. 18 As coordenadas cristalográficas foram convertidas para coordenadas cartesianas e a estrutura foi editada para a retirada do íon Na + e das moléculas de água não-coordenadas ao íon central. A estrutura editada serviu como arranjo inicial para os cálculos apresentados nesse estudo.…”

Section: Metodologiaunclassified

A Simple Strategy That Uses Molecular Dynamics and Semiempirical Methods for the Conformational Searching of isomers of the Macrocycle Complex Na[Gd(DOTA)·H2O]

Oliveira¹,

Farias²,

Santana³

et al. 2017

Rev. Virtual Quim.

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Supramolecular compounds containing lanthanides, in particular the Gd (III) ion, are increasingly being used as contrast agents in the medical diagnosis technique Magnetic Resonance Imaging, MRI. Thus, the molecular modeling and simulation of these complexes are indispensable to study their structures and dynamics in solution. In this paper, a conformational study of the macrocyclic complex [Gd(DOTA)·H 2 O] -, where DOTA is an abbreviation for the 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid, has been performed. For this, we carried out a procedure involving the mapping or sampling of the conformational space of such compound via short molecular dynamics at different temperatures. Each final geometry was used as starting point for geometry optimization using RM1 semiempirical quantum chemistry method. The four stable conformers A1, IA1, IA2 and A2 were found through detailed analysis of geometric (bond length distances, dihedral angles, etc.) and energy (H f and Gibbs energy) data of all optimized structures. In addition, we also have found structures of minimum energy that we point out as intermediate geometries (not transition states) between two conformational isomers. Through this study, we developed a simple strategy to perform the search for conformational isomers of this type of compound. These details are very important when designing new molecules to act as efficient contrast agents in MRI.Keywords: Conformational Analysis; Molecular Dynamics; RM1; Gadolinium Macrocycles. ResumoCompostos supramoleculares contendo íons lantanídeos, em especial o íon Gd(III), são cada vez mais utilizados como agentes de contraste na técnica de diagnóstico imagem por ressonância magnética nuclear, MRI. Com isso, a modelagem e simulação molecular destes complexos são indispensáveis para estudar suas estruturas e dinâmicas em solução. Neste trabalho foi realizado um estudo conformacional do complexo macrocíclico [Gd(DOTA)H 2 O] -, onde DOTA é uma abreviação para o ácido 1,4,7,10-tetraazaciclododecano-1,4,7,10-tetraacético. Para isso, realizamos um procedimento que envolve o mapeamento ou amostragem do espaço conformacional desse composto através de dinâmicas moleculares curtas em diferentes temperaturas para, em seguida, as geometrias serem usadas como pontos de partida para otimização de geometria usando o método semiempírico RM1. Os quatro confórmeros estáveis A1, IA1, A2 e IA2 foram encontrados através da análise detalhada de dados geométricos (distâncias de ligação, diedros, distância entre planos, etc.) e energéticos (H f e energia de Gibbs) de todas as estruturas geradas. Além dessas conformações, encontramos ainda estruturas de energia mínima que entendemos como sendo intermediárias (não estados de transição) entre dois isômeros conformacionais. Através deste estudo elaboramos uma estratégia simples para realizar a busca de isômeros conformacionais de compostos desse tipo, sendo essas informações muito importantes quando se deseja projetar novas moléculas para atuarem como eficientes agentes ...

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“…The geometry of [Gd(DOTA)(H 2 O)] -has been taken from the published crystal structure [22] and therefore the SA isomer in its ∆(λλλλ) form (=A1, M1 in [23]). The DFT calculations correspond to a single molecule in vacuum.…”

Section: Computational Detailsmentioning

confidence: 99%

Electronic fine structure calculation of [Gd(DOTA)(H2O)]– using LF-DFT: The zero field splitting

Senn

Helm²,

Borel

et al. 2011

Comptes Rendus. Chimie

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Synthesis, characterization, and crystal structures of M(DO3A) (M = iron, gadolinium) and Na[M(DOTA)] (M = Fe, yttrium, Gd)

Abstract: Macrocyclic amino carboxylate (DOTA and D03A, where DOTA is l,4,7,10-tetrakis(carboxymethyl)-l,4,7,10-

Cited by 269 publications

References 0 publications

Managing the solvent water polarization to obtain improved NMR spectra of large molecular structures

Managing the solvent water polarization to obtain improved NMR spectra of large molecular structures

A Simple Strategy That Uses Molecular Dynamics and Semiempirical Methods for the Conformational Searching of isomers of the Macrocycle Complex Na[Gd(DOTA)·H2O]

Electronic fine structure calculation of [Gd(DOTA)(H2O)]– using LF-DFT: The zero field splitting

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