TY - JOUR
T1 - 25Mg NMR Studies of magnesium binding to erythrocyte constituents
AU - Bock, Jay L.
AU - Crull, George B.
AU - Wishnia, Arnold
AU - Springer, Charles S.
N1 - Funding Information:
We thank the National Science Foundation and the National instiiute.s r>,fH‘ ealth for grants Nos. DMB-8715852 and GM32125, respectivel_vi,o C‘SS; the American Heart Association, Westchester:P utnurn Chapter, for a Grunt-in-Aid to LB; und the INational Institutes of Health BRSG program, grant No. RR05736, fbr support tu JIB. UC thank Dr. Yan Xu,for help with our initial “/cQ NMU experiment+a nd D?. Rohiw Rr>wzi liw his comments.
PY - 1991/11/1
Y1 - 1991/11/1
N2 - The binding of Mg2+ ion to ATP, ADP, AMP, 2,3-bisphosphyoglycerate (DPG), and hemoglobin has been studied by 25Mg NMR spectroscopy at 9.4 T. Addition of any of these ligands to a solution of 2 mM25MgCl at pH 7.2 caused a progressive increase in linewidth, with no discernible chemical shift. ATP and ADP, which form tight 1:1 complexes with Mg2+, did not cause maximal broadening until present in several-fold excess, implying that bis(nucleotide) complexes also form. The studies showed progressively weaker Mg2+ binding to ATP, ADP, DPG, and AMP, consistent with published binding constants. Hemoglobin cause fairly little broadening, consistent with its known weak affinity for Mg2+. Competition studies determined ATP affinities for Ca2+ and H+ that were also in good agreement with published values. 25Mg NMR spectra of 2 mM bound 25Mg2+ were obtained with good signal to noise in less than 1 hr. The technique may now be a practical means for studying the binding of Mg2+ within erythrocytes and other cells.
AB - The binding of Mg2+ ion to ATP, ADP, AMP, 2,3-bisphosphyoglycerate (DPG), and hemoglobin has been studied by 25Mg NMR spectroscopy at 9.4 T. Addition of any of these ligands to a solution of 2 mM25MgCl at pH 7.2 caused a progressive increase in linewidth, with no discernible chemical shift. ATP and ADP, which form tight 1:1 complexes with Mg2+, did not cause maximal broadening until present in several-fold excess, implying that bis(nucleotide) complexes also form. The studies showed progressively weaker Mg2+ binding to ATP, ADP, DPG, and AMP, consistent with published binding constants. Hemoglobin cause fairly little broadening, consistent with its known weak affinity for Mg2+. Competition studies determined ATP affinities for Ca2+ and H+ that were also in good agreement with published values. 25Mg NMR spectra of 2 mM bound 25Mg2+ were obtained with good signal to noise in less than 1 hr. The technique may now be a practical means for studying the binding of Mg2+ within erythrocytes and other cells.
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U2 - 10.1016/0162-0134(91)84020-A
DO - 10.1016/0162-0134(91)84020-A
M3 - Article
C2 - 1787415
AN - SCOPUS:0025918443
SN - 0162-0134
VL - 44
SP - 79
EP - 87
JO - Journal of Inorganic Biochemistry
JF - Journal of Inorganic Biochemistry
IS - 2
ER -