Isomeric equilibria in complexes of adenosine 5'-triphosphate with divalent metal ions. Solution structures of M(ATP)2- complexes. Export

@article{sigel:87, abstract = {Solution structures of M(ATP)2- complexes are reviewed. First the self-stacking properties of ATP4- and M(ATP)2- are shortly described. It is emphasized that for an evaluation of solution structures of M(ATP)2- complexes only results from diluted solutions (below 1 mM) should be used. Next, a comprehensive set of stability data obtained under such conditions from potentiometric pH titrations is summarized for the complexes of Mg2+, Ca2+, Mn2+, Co2+, Ni2+, Cu2+, Zn2+ and Cd2+ with ATP, and for comparison also with pyrimidine nucleoside 5'-triphosphates (YTPs), i.e. CTP, UTP and TTP. The stabilities for the M(ATP)2- complexes are mostly larger than those for the corresponding M(YTP)2- species; this increased stability results from the metal ion back-binding to the base residue in M(ATP)2-, i.e. macrochelates are formed. Detailed analysis of the stability data allows calculation of the percentage of the closed form for the several M(ATP)2- complexes: back-binding is most pronounced in Cu(ATP)2- (67 +/- 2\%), remarkable in Zn(ATP)2- (28 +/- 7\%), and not observable for Ca(ATP)2- (2 +/- 6\%). Comparison of these results with those from 1H-NMR and ultraviolet spectrophotometric studies allows the conclusion that two types of base back-bound macrochelates are formed: one with a direct, i.e. innersphere, M2+/N-7 coordination, and one with a water molecule between the metal ion and N-7, i.e. an outersphere interaction occurs [e.g. to about 10\% in Mg(ATP)2-] through hydrogen bonding of a coordinated water to N-7. The formation degree of both forms of these closed isomers is quantified. The biological implications of these results are indicated and the versatility of ATP as a ligand is discussed by summarizing pertinent examples.}, author = {Sigel, H.}, citeulike-article-id = {3862579}, citeulike-linkout-0 = {http://view.ncbi.nlm.nih.gov/pubmed/3569298}, citeulike-linkout-1 = {http://www.hubmed.org/display.cgi?uids=3569298}, day = {15}, issn = {0014-2956}, journal = {European journal of biochemistry / FEBS}, keywords = {atp}, month = {May}, number = {1}, pages = {65--72}, posted-at = {2009-01-08 19:33:43}, priority = {0}, title = {Isomeric equilibria in complexes of adenosine 5'-triphosphate with divalent metal ions. Solution structures of M(ATP)2- complexes.}, url = {http://view.ncbi.nlm.nih.gov/pubmed/3569298}, volume = {165}, year = {1987} }

TY - JOUR ID - sigel:87 L3 - citeulike-article-id:3862579 N2 - Solution structures of M(ATP)2- complexes are reviewed. First the self-stacking properties of ATP4- and M(ATP)2- are shortly described. It is emphasized that for an evaluation of solution structures of M(ATP)2- complexes only results from diluted solutions (below 1 mM) should be used. Next, a comprehensive set of stability data obtained under such conditions from potentiometric pH titrations is summarized for the complexes of Mg2+, Ca2+, Mn2+, Co2+, Ni2+, Cu2+, Zn2+ and Cd2+ with ATP, and for comparison also with pyrimidine nucleoside 5'-triphosphates (YTPs), i.e. CTP, UTP and TTP. The stabilities for the M(ATP)2- complexes are mostly larger than those for the corresponding M(YTP)2- species; this increased stability results from the metal ion back-binding to the base residue in M(ATP)2-, i.e. macrochelates are formed. Detailed analysis of the stability data allows calculation of the percentage of the closed form for the several M(ATP)2- complexes: back-binding is most pronounced in Cu(ATP)2- (67 +/- 2%), remarkable in Zn(ATP)2- (28 +/- 7%), and not observable for Ca(ATP)2- (2 +/- 6%). Comparison of these results with those from 1H-NMR and ultraviolet spectrophotometric studies allows the conclusion that two types of base back-bound macrochelates are formed: one with a direct, i.e. innersphere, M2+/N-7 coordination, and one with a water molecule between the metal ion and N-7, i.e. an outersphere interaction occurs [e.g. to about 10% in Mg(ATP)2-] through hydrogen bonding of a coordinated water to N-7. The formation degree of both forms of these closed isomers is quantified. The biological implications of these results are indicated and the versatility of ATP as a ligand is discussed by summarizing pertinent examples. IS - 1 JF - European journal of biochemistry / FEBS SN - 0014-2956 EP - 72 TI - Isomeric equilibria in complexes of adenosine 5'-triphosphate with divalent metal ions. Solution structures of M(ATP)2- complexes. VL - 165 SP - 65 KW - atp AU - Sigel, H PY - 1987/05/15/ UR - http://view.ncbi.nlm.nih.gov/pubmed/3569298 ER -