Interaction of divalent metal ions with pyridoxal phosphate. I. Nuclear magnetic resonance studies of cobalt(II) binding

1980 ◽  
Vol 58 (11) ◽  
pp. 1118-1124 ◽  
Author(s):  
Tenkasi S. Viswanathan ◽  
Terrence J. Swift
Keyword(s):  
Metal Ion ◽  
Pyridoxal Phosphate ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Proton Spin ◽  
Spin Lattice Relaxation ◽  
Methylene Proton ◽  
Divalent Metal Ions ◽  
Spin Lattice ◽  
Neutral Ph

The binding of Co(II) to pyridoxal phosphate (PLP)at neutral pH was investigated with 31P, 1H, and 13C nmr spectroscopy. The proton and phosphorus spin–lattice relaxation times of PLP were measured in the absence of Co(II) and with increasing amounts of the metal ion. The shifting and the relaxation enhancement of the phosphorus resonance in the presence of Co(II) have indicated the binding of the metal ion to the phosphate of PLP. The addition of metal ion also shifted and broadened the proton and carbon resonances. The shifting and broadening was the largest for the 4-CHO proton with other protons following the order 4-CHO [Formula: see text] 2-methyl > 5-methylene > 6-H. At neutral pH Co(II) shifted only the 5-methylene proton resonance of pyridoxamine phosphate (PMP) indicating binding of Co(II) only to the 5′-phosphate of PMP at this pH. Comparison of the shifting and broadening of the proton resonances of PLP with similar shifts in model compounds has indicated a structure for the 1:1 PLP:Co(II) complex in which the metal ion is simultaneously bound to the phosphate and the aldehyde oxygen. The proton spin–lattice relaxation times and the isotropic shifts of the 13C resonances in the 1:1 PLP:Co(II) complex support this conclusion.

PROTON SPIN-LATTICE RELAXATION TIMES OF HUMIC ACIDS AS DETERMINED BY SOLUTION NMR

Soil Science ◽  
2003 ◽  
Vol 168 (2) ◽  
pp. 128-136 ◽  
Author(s):  
Kaijun Wang ◽  
L. Charles Dickinson ◽  
Elham A. Ghabbour ◽  
Geoffrey Davies ◽  
Baoshan Xing
Keyword(s):  
Humic Acids ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Proton Spin ◽  
Spin Lattice Relaxation ◽  
Solution Nmr ◽  
Spin Lattice

Histopathological Evidence in Support of the Association of Elevated Proton Spin-lattice Relaxation Times with the Malignant State

1979 ◽  
Vol 65 (2) ◽  
pp. 157-162 ◽  
Author(s):  
S. S. Ranade ◽  
Smita Shah ◽  
G. V. Talwalkar
Keyword(s):  
Human Cancer ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Malignant Cell ◽  
Proton Spin ◽  
Spin Lattice Relaxation ◽  
Histopathological Study ◽  
Spin Lattice ◽  
Malignant State ◽  
T Values

The pulsed nuclear magnetic resonance technique was explored for its potential diagnostic value in human cancer. Measurements of proton spin-lattice relaxation times (T1) of cellular water protons of normal and malignant esophageal tissues showed elevated T, values in the latter. In some cases, tissues which appeared normal on gross examination assumed as uninvolved tissues had T, values higher than the other grossly uninvolved tissues and often closer to the T, of the corresponding tumor tissue. A histopathological study of the assumed uninvolved areas also studied for the T, values was therefore undertaken. A preliminary study demonstrated the presence of malignant cell groups or clusters in some of the uninvolved samples with higher T1 compared to the true uninvolved tissues, which had a normal histological picture and low T, values. This observation has brought out the importance of histopathological studies in addition to relaxation studies to comprehend contributory factors to relaxation. Secondly, it lends support to the thesis of elevated T, values being characteristics of the malignant state.

A study of 14N relaxation and nitrogen–proton spin coupling in Watson–Crick base pair models through Fourier transform measurements on NH proton spin–lattice relaxation in the rotating frame

1979 ◽  
Vol 57 (9) ◽  
pp. 1075-1079 ◽  
Author(s):  
Michael E. Moseley ◽  
Peter Stilbs
Keyword(s):  
Relaxation Times ◽  
Lattice Relaxation ◽  
Proton Spin ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Spin Lattice Relaxation ◽  
Indirect Measurements ◽  
Spin Lattice ◽  
Proton Coupling ◽  
Nuclear Spin Lattice Relaxation

Indirect measurements of nitrogen-14 nuclear spin-lattice relaxation times and direct proton coupling constants are presented together with carbon-13 T1 data for a series of alkyl-substituted nucleic acid bases and mixtures thereof in DMSO-d6. With the exception of the guanine NH nitrogen, which possibly experiences a decrease in the electric field gradient upon complexation with cytosine, no indications of significant changes in the electronic environment around the nitrogen nuclei were found for any combination of bases. Forsen–Hoffman spin saturation transfer experiments on the NH and NH2 protons are also presented.

A nuclear magnetic resonance study of pyridoxal phosphate – metal ion interactions. II. Binding of manganese(II)

1979 ◽  
Vol 57 (9) ◽  
pp. 1050-1055 ◽  
Author(s):  
Tenkasi S. Viswanathan ◽  
Terrence J. Swift
Keyword(s):  
Metal Ion ◽  
Pyridoxal Phosphate ◽  
Lattice Relaxation ◽  
Dipolar Interaction ◽  
Rotational Correlation Time ◽  
Nuclear Magnetic Resonance Study ◽  
Spin Lattice Relaxation ◽  
Relaxation Rates ◽  
Spin Lattice ◽  
Nmr Methods

The line width and spin–lattice relaxation rates of phosphorus and proton nuclei in PLP have been measured as a function of temperature in the presence of Mn(II) using pulsed nmr methods. The T1M of 31P in PLP-Mn(II) is very close to the T1M values of β- and γ-phosphorus atoms in ATP–Mn(II) at ∼40 °C. The T1 data of 31P and 1H have been interpreted in terms of the dipolar interaction between the electron and nuclear spins. With the assumption that the Mn(II) interacts directly with the phosphate of PLP the rotational correlation time τc at 38 °C was calculated to be 7.6 × 10−10 s from phosphorus T1 data. This τc value was subsequently used to calculate metal–proton distances from proton T1 and T2 data. The results lead to the conclusion that the phosphate-bound metal interacts directly with the aldehyde oxygen in a 1:1 PLP–Mn(II) complex. The linewidth of the 13C resonances of PLP in the presence of Mn(II) supports this conclusion. The structure assigned for PLP–Mn(II) complex is in conformity with the structure for PLP-Co(II) complex.

Intermolecular potentials from NMR data: H2–N2O and H2–CO2

1983 ◽  
Vol 61 (5) ◽  
pp. 664-670 ◽  
Author(s):  
Lakshman Pandey ◽  
C. P. K. Reddy ◽  
K. Lalita Sarkar
Keyword(s):  
Relaxation Times ◽  
Lattice Relaxation ◽  
Proton Spin ◽  
Spin Lattice Relaxation ◽  
Intermolecular Potential ◽  
Quadrupole Moments ◽  
Spin Lattice ◽  
Lennard Jones ◽  
Nmr Data ◽  
Potential Parameters

Proton spin-lattice relaxation times T1 were measured in mixtures of H2 with N2O as a function of density, composition, and temperature (200–400 K) in the region where [Formula: see text]. These data, along with the data obtained by Lalita and Bloom for H2–CO2, were interpreted, using Bloom–Oppenheim theory, to obtain the anisotropic intermoleeular potential parameters. Two models, (i) the Lennard–Jones (12–6) potential (LJP) and (ii) the modified Buckingham (exp-6) potential (MBP), were used to represent the isotropic part of the intermolecular potential. The relative anisotropy in the attractive r−6 term and the quadrupole moments of N2O and CO2 as obtained from MBP model are in better agreement with the values obtained from the polarizability data and the reported values, respectively, than those obtained from the LJP model.

The water proton spin-lattice relaxation times in virus-infected cells

1979 ◽  
Vol 10 (2) ◽  
pp. 143-146 ◽  
Author(s):  
Gianni Valensin ◽  
Elena Gaggelli ◽  
Enzo Tiezzi ◽  
Pier Egisto Valensin ◽  
Maria L.Bianchi Bandinelli
Keyword(s):  
Relaxation Times ◽  
Lattice Relaxation ◽  
Proton Spin ◽  
Spin Lattice Relaxation ◽  
Water Proton ◽  
Spin Lattice ◽  
Infected Cells
Sign in / Sign up

Export Citation Format

Share Document