Evaluation of [Co(gly)3]- as a 35Cl- NMR shift reagent for cellular studies

Conrad F. Diven; Fei Wang; Abde M. Abukhdeir; Wajeeh Salah; Brian T. Layden; Carlos F G C Geraldes; Duarte Mota De Freitas

doi:10.1021/ic0258680

Evaluation of [Co(gly)₃]^- as a ³⁵Cl^- NMR shift reagent for cellular studies

Conrad F. Diven, Fei Wang, Abde M. Abukhdeir, Wajeeh Salah, Brian T. Layden, Carlos F G C Geraldes, Duarte Mota De Freitas

Medicine, Endocrinology Division

Research output: Contribution to journal › Article › peer-review

6 Scopus citations

Abstract

We studied the efficacy of the tris-glycinatocobaltate(II) complex ([Co(gly)₃]^-) as a shift reagent (SR) for chloride by ³⁵Cl NMR spectroscopy and compared to that of Co²⁺_(aq). Due to the relatively low thermodynamic stability of [Co(gly)₃]^-, a 1:3 Co(II)/gly stoichiometric solution at physiological pH is approximately a 2:1 mixture of [Co(gly)₂-(H₂O)₂] and [Co(gly)(H₂O)₄]⁺. This SR was found to be stable up to higher pH values than Co²⁺_(aq), better preventing Co(OH)₂ formation at alkaline pH. No significant differences in the ³⁵Cl^- NMR chemical shift induced by Co(II)/gly or Co²⁺_(aq) were observed in the presence of physiological concentrations of either Ca²⁺ or Mg²⁺, or of either Na⁺ or K⁺. Although Co²⁺_(aq) was almost twice as effective as Co(II)/gly in shifting the ³⁵Cl^- NMR resonance at the same high ρ ([SR]/[Cl^-]) value and low ionic strength, Co²⁺_(aq) showed a significant decrease (p < 0.05) in the ³⁵Cl^- chemical shift at higher ionic strength. Line widths at half-height were significantly (p < 0.05) less for Co-(II)/gly than for Co²⁺_(aq) at ρ values in the range 0.066-0.40. Intracellular chloride was clearly detectable by ³⁵Cl NMR spectroscopy in human skin fibroblast cells suspended in medium containing 40 mM Co(II)/gly SR. We determined that, although Co²⁺_(aq) provides a larger shift than Co(II)/gly at the same ρ value, there are significant advantages for using Co(II)/gly, such as pH stability, ionic strength independent chemical shifts, narrow ³⁵Cl^- NMR resonances, and reduced cellular toxicity, as a SR in biological systems.

Original language	English (US)
Pages (from-to)	2774-2782
Number of pages	9
Journal	Inorganic chemistry
Volume	42
Issue number	8
DOIs	https://doi.org/10.1021/ic0258680
State	Published - Apr 21 2003

ASJC Scopus subject areas

Inorganic Chemistry
Physical and Theoretical Chemistry

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@article{ee24a1b6c54a4cecadc0595e5b1bd6cc,

title = "Evaluation of [Co(gly)3]- as a 35Cl- NMR shift reagent for cellular studies",

abstract = "We studied the efficacy of the tris-glycinatocobaltate(II) complex ([Co(gly)3]-) as a shift reagent (SR) for chloride by 35Cl NMR spectroscopy and compared to that of Co2+(aq). Due to the relatively low thermodynamic stability of [Co(gly)3]-, a 1:3 Co(II)/gly stoichiometric solution at physiological pH is approximately a 2:1 mixture of [Co(gly)2-(H2O)2] and [Co(gly)(H2O)4]+. This SR was found to be stable up to higher pH values than Co2+(aq), better preventing Co(OH)2 formation at alkaline pH. No significant differences in the 35Cl- NMR chemical shift induced by Co(II)/gly or Co2+(aq) were observed in the presence of physiological concentrations of either Ca2+ or Mg2+, or of either Na+ or K+. Although Co2+(aq) was almost twice as effective as Co(II)/gly in shifting the 35Cl- NMR resonance at the same high ρ ([SR]/[Cl-]) value and low ionic strength, Co2+(aq) showed a significant decrease (p < 0.05) in the 35Cl- chemical shift at higher ionic strength. Line widths at half-height were significantly (p < 0.05) less for Co-(II)/gly than for Co2+(aq) at ρ values in the range 0.066-0.40. Intracellular chloride was clearly detectable by 35Cl NMR spectroscopy in human skin fibroblast cells suspended in medium containing 40 mM Co(II)/gly SR. We determined that, although Co2+(aq) provides a larger shift than Co(II)/gly at the same ρ value, there are significant advantages for using Co(II)/gly, such as pH stability, ionic strength independent chemical shifts, narrow 35Cl- NMR resonances, and reduced cellular toxicity, as a SR in biological systems.",

author = "Diven, {Conrad F.} and Fei Wang and Abukhdeir, {Abde M.} and Wajeeh Salah and Layden, {Brian T.} and Geraldes, {Carlos F G C} and {De Freitas}, {Duarte Mota}",

year = "2003",

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doi = "10.1021/ic0258680",

language = "English (US)",

volume = "42",

pages = "2774--2782",

journal = "Inorganic chemistry",

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T1 - Evaluation of [Co(gly)3]- as a 35Cl- NMR shift reagent for cellular studies

AU - Diven, Conrad F.

AU - Wang, Fei

AU - Abukhdeir, Abde M.

AU - Salah, Wajeeh

AU - Layden, Brian T.

AU - Geraldes, Carlos F G C

AU - De Freitas, Duarte Mota

PY - 2003/4/21

Y1 - 2003/4/21

N2 - We studied the efficacy of the tris-glycinatocobaltate(II) complex ([Co(gly)3]-) as a shift reagent (SR) for chloride by 35Cl NMR spectroscopy and compared to that of Co2+(aq). Due to the relatively low thermodynamic stability of [Co(gly)3]-, a 1:3 Co(II)/gly stoichiometric solution at physiological pH is approximately a 2:1 mixture of [Co(gly)2-(H2O)2] and [Co(gly)(H2O)4]+. This SR was found to be stable up to higher pH values than Co2+(aq), better preventing Co(OH)2 formation at alkaline pH. No significant differences in the 35Cl- NMR chemical shift induced by Co(II)/gly or Co2+(aq) were observed in the presence of physiological concentrations of either Ca2+ or Mg2+, or of either Na+ or K+. Although Co2+(aq) was almost twice as effective as Co(II)/gly in shifting the 35Cl- NMR resonance at the same high ρ ([SR]/[Cl-]) value and low ionic strength, Co2+(aq) showed a significant decrease (p < 0.05) in the 35Cl- chemical shift at higher ionic strength. Line widths at half-height were significantly (p < 0.05) less for Co-(II)/gly than for Co2+(aq) at ρ values in the range 0.066-0.40. Intracellular chloride was clearly detectable by 35Cl NMR spectroscopy in human skin fibroblast cells suspended in medium containing 40 mM Co(II)/gly SR. We determined that, although Co2+(aq) provides a larger shift than Co(II)/gly at the same ρ value, there are significant advantages for using Co(II)/gly, such as pH stability, ionic strength independent chemical shifts, narrow 35Cl- NMR resonances, and reduced cellular toxicity, as a SR in biological systems.

AB - We studied the efficacy of the tris-glycinatocobaltate(II) complex ([Co(gly)3]-) as a shift reagent (SR) for chloride by 35Cl NMR spectroscopy and compared to that of Co2+(aq). Due to the relatively low thermodynamic stability of [Co(gly)3]-, a 1:3 Co(II)/gly stoichiometric solution at physiological pH is approximately a 2:1 mixture of [Co(gly)2-(H2O)2] and [Co(gly)(H2O)4]+. This SR was found to be stable up to higher pH values than Co2+(aq), better preventing Co(OH)2 formation at alkaline pH. No significant differences in the 35Cl- NMR chemical shift induced by Co(II)/gly or Co2+(aq) were observed in the presence of physiological concentrations of either Ca2+ or Mg2+, or of either Na+ or K+. Although Co2+(aq) was almost twice as effective as Co(II)/gly in shifting the 35Cl- NMR resonance at the same high ρ ([SR]/[Cl-]) value and low ionic strength, Co2+(aq) showed a significant decrease (p < 0.05) in the 35Cl- chemical shift at higher ionic strength. Line widths at half-height were significantly (p < 0.05) less for Co-(II)/gly than for Co2+(aq) at ρ values in the range 0.066-0.40. Intracellular chloride was clearly detectable by 35Cl NMR spectroscopy in human skin fibroblast cells suspended in medium containing 40 mM Co(II)/gly SR. We determined that, although Co2+(aq) provides a larger shift than Co(II)/gly at the same ρ value, there are significant advantages for using Co(II)/gly, such as pH stability, ionic strength independent chemical shifts, narrow 35Cl- NMR resonances, and reduced cellular toxicity, as a SR in biological systems.

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JO - Inorganic chemistry

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Evaluation of [Co(gly)₃]^- as a ³⁵Cl^- NMR shift reagent for cellular studies

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