Effect of Metal Coordination on the Charge Distribution over the Cation Binding Sites of Zeolites. A Combined Experimental and Theoretical Study

2001 ◽  
Vol 105 (35) ◽  
pp. 8285-8290 ◽  
Author(s):  
Judit E. Šponer ◽  
Zdeněk Sobalík ◽  
Jerzy Leszczynski ◽  
Blanka Wichterlová
Keyword(s):  
Charge Distribution ◽  
Binding Sites ◽  
Theoretical Study ◽  
Cation Binding ◽  
Metal Coordination

Determination of copper binding sites in peptides containing basic residues: a combined experimental and theoretical study

2001 ◽  
Vol 204 (1-3) ◽  
pp. 31-46 ◽  
Author(s):  
Brian K. Bluhm ◽  
Sharon J. Shields ◽  
Craig A. Bayse ◽  
Michael B. Hall ◽  
David H. Russell
Keyword(s):  
Binding Sites ◽  
Theoretical Study ◽  
Copper Binding ◽  
Determination Of Copper ◽  
Copper Binding Sites

scholarly journals First Characterization of an Archaeal GTP-Dependent Phosphoenolpyruvate Carboxykinase from the Hyperthermophilic Archaeon Thermococcus kodakaraensis KOD1

2004 ◽  
Vol 186 (14) ◽  
pp. 4620-4627 ◽  
Author(s):  
Wakao Fukuda ◽  
Toshiaki Fukui ◽  
Haruyuki Atomi ◽  
Tadayuki Imanaka
Keyword(s):  
Binding Sites ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Cation Binding ◽  
Activity Levels ◽  
Binding Region ◽  
Hyperthermophilic Archaeon ◽  
Dependent Activity ◽  
Additional Role

ABSTRACT Phosphoenolpyruvate carboxykinase (PCK), which catalyzes the nucleotide-dependent, reversible decarboxylation of oxaloacetate to yield phosphoenolpyruvate and CO2, is one of the important enzymes in the interconversion between C3 and C4 metabolites. This study focused on the first characterization of the enzymatic properties and expression profile of an archaeal PCK from the hyperthermophilic archaeon Thermococcus kodakaraensis (Pck Tk ). Pck Tk showed 30 to 35% identities to GTP-dependent PCKs from mammals and bacteria but was located in a branch distinct from that of the classical enzymes in the phylogenetic tree, together with other archaeal homologs from Pyrococcus and Sulfolobus spp. Several catalytically important regions and residues, found in all known PCKs irrespective of their nucleotide specificities, were conserved in Pck Tk . However, the predicted GTP-binding region was unique compared to those in other GTP-dependent PCKs. The recombinant Pck Tk actually exhibited GTP-dependent activity and was suggested to possess dual cation-binding sites specific for Mn2+ and Mg2+. The enzyme preferred phosphoenolpyruvate formation from oxaloacetate, since the Km value for oxaloacetate was much lower than that for phosphoenolpyruvate. The transcription and activity levels in T. kodakaraensis were higher under gluconeogenic conditions than under glycolytic conditions. These results agreed with the role of Pck Tk in providing phosphoenolpyruvate from oxaloacetate as the first step of gluconeogenesis in this hyperthermophilic archaeon. Additionally, under gluconeogenic conditions, we observed higher expression levels of Pck Tk on pyruvate than on amino acids, implying that it plays an additional role in the recycling of excess phosphoenolpyruvate produced from pyruvate, replacing the function of the anaplerotic phosphoenolpyruvate carboxylase that is missing from this archaeon.

scholarly journals Synthesis and Photoregulated Metal Coordination of Azobenzene Polymer Having Ion Binding Sites

1991 ◽  
Vol 23 (2) ◽  
pp. 127-134 ◽  
Author(s):  
Masato Nanasawa ◽  
Takahiro Nishiyama ◽  
Hiroyoshi Kamogawa
Keyword(s):  
Binding Sites ◽  
Metal Coordination ◽  
Ion Binding ◽  
Azobenzene Polymer ◽  
Ion Binding Sites

scholarly journals The structural chemistry of zinc(ii) and nickel(ii) dithiocarbamate complexes

2021 ◽  
Vol 19 (1) ◽  
pp. 974-986
Author(s):  
Tanzimjahan A. Saiyed ◽  
Jerry O. Adeyemi ◽  
Damian C. Onwudiwe
Keyword(s):  
Complex Formation ◽  
Metal Ions ◽  
Structural Properties ◽  
Binding Sites ◽  
Biological Systems ◽  
Structural Chemistry ◽  
Metal Coordination ◽  
Nickel Ions ◽  
Coordination Modes ◽  
Biomedical Fields

Abstract Dithiocarbamate complexes are of immense interest due to their diverse structural properties and extensive application in various areas. They possess two sulfur atoms that often act as the binding sites for metal coordination in a monodentate, bidentate, or anisodentate fashion. These different coordination modes enhance the possibility for complex formation and make them useful in different areas especially in biomedical fields. A synergy exists in the metal ions and dithiocarbamate moieties, which tends to exert better properties than the respective individual components of the complex. These improved properties have also been attributed to the presence of the C–S bonds. Zinc and nickel ions have been majorly found to bind to the dithiocarbamate in bidentate modes, and consequently different geometries have resulted from this interaction. The aim of this review is to present some studies on the synthesis, structural chemistry, and the relevance of zinc and nickel dithiocarbamates complexes especially in biological systems.

Furosemide-sensitive thallium fluxes in smooth muscle of rabbit uterus

1983 ◽  
Vol 245 (6) ◽  
pp. F778-F783
Author(s):  
A. Johns ◽  
S. V. Cutshaw
Keyword(s):  
Smooth Muscle ◽  
Binding Sites ◽  
Rank Order ◽  
Chloride Concentration ◽  
Cation Binding ◽  
Exchange System ◽  
Total Uptake ◽  
Low Concentrations ◽  
Chloride Pump ◽  
High Concentrations

The furosemide-sensitive uptake of thallium represents approximately equal to 50% of the total uptake of thallium by rabbit uterus and requires Cl- and Na+. The furosemide-sensitive uptake of thallium is stimulated by other ions at low concentrations with the rank order Li+ greater than Tl+ greater than K+ = Rb+ greater than Cs+ and is inhibited by these ions at high concentrations with the rank order Tl+ greater than K+ = Rb+ greater than Cs+ greater than Li+, suggesting multiple cation binding sites on the carrier. Uptake of 36Cl- is inhibited by furosemide in the presence of ouabain. Thallium efflux and 36Cl efflux in the presence of ouabain is inhibited by furosemide. The chloride concentration regulates the proportion of thallium uptake that is ouabain sensitive and furosemide sensitive without altering the total uptake. It is suggested that the furosemide-sensitive uptake of thallium reflects a Na+-Cl- -K+ exchange system that could be classified as a cotransport or countertransport of any two of these ions and also could be the smooth muscle chloride pump.

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