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Zastosowanie spektroskopii jądrowego rezonansu magnetycznego w badaniach oddziaływań międzycząsteczkowych ligandów organicznych i biocząsteczek

Bocian W., Kozerski L.

Wiadomości Chemiczne

2005

[Z] 59, 1-2

3--22

The title problem is reviewed in the three main areas of general interest to chemists, biochemists and biologists, i.e. mutual interactions of small molecules, ligand to biomolecule binding and interactions of biomolecules. Physical phenomena, specific and nonspecific, such as hydrogen bonding, self association, hydrophobic interactions, etc., are shown as being defined by NMR spectral parameters in solution and solid state. Diversity of hydrogen bonding encountered in nature is exemplified by the interaction of acetic acid with Watson-Crick vs Hoogsteen faces of adenosine, studied by DNMR in organic solvent at low temperatures. The complementarity of solid state NMR to solution studies of defining the nature of hydrogen bonding is presented in the case of genistein interaction with nitrogen bases. Application of a title method is presented for searching the geometry of complexes formed of organic ligands and biological molecules. General protocol for searching the geometry of complex is presented for the case of topotecan (TPT) interaction with duplex octamer and nicked decamer duplexes of DNA. Interaction of biomolecules is presented for the case of duplex octamer DNMR study showing effects of base pairing and stacking on the b 'H values and insulin aggregation as studied by Pulse Field Gradient NMR spectroscopy leading to relating the radius of molecular aggregate with the diffusion constants. In conclusion it is stated that various NMR techniques in solid and liquid state, coupled with X-ray and MS, constitute modern tool of structural biology in pursue of disclosing functions of biomolecules expressed by their interactions.

Właściwości koordynacyjne ligandów z ugrupowaniem fosfonowym z wybranymi jonami metali

Kamecka A., Kurzak B.

Wiadomości Chemiczne

2003

[Z] 57, 9-10

797--825

Aminopolyphosphonic acids and their derivatives have received considerable attention because of their interesting biological activity and a wide range of uses for industrial, chemical, agricultural and pharmacological purposes. The area of metal phosphonate chemistry has developed significantly in the last three decade. The coordination chemistry of this group of ligands is rich due to their versatility in adopting monodentate, bridging and chelating modes of coordination. Phosphonates and aminophosphonates are potent chelating agents for variety metal ions including the alkaline earth ions, the divalent ions as well as the trivalent ions. In this article we are summarizing and discussing the acid-base properties and the metal ion-coordinating properties of compounds involving one, two or more phosphonic groups. This work is aimed at being brief indicating the main achievements in researches over coordination preferences of this group of ligands. The present considerations are restricted to complexes in solution, involving the alkaline earth ions and the divalent ions of the second half of the 3d series as well as Zn2+ and Cd2+. The acid-base properties of the considered ligands depend on many factors such as the number of phosphonic groups in one molecule, the presence of other functional groups (e.g. COOH, NH3+, OH), the distance between functional groups and electronic effects of the substituents. These ligands contain a range of potential donor atoms. As a result, various bonding modes for a given chelating ligand are involved, and are reviewed with reference to ligand structure and the resulting coordination complexes. It is shown that depending on the pH and the nature of the metal ion in solution these ligands can bind to a metal ion via oxygen(s) (mostly with alkaline earth ions), and in a N,O bonding mode (usually with d metals). Coordination properties of phosphonic and aminophosphonic acids are important factors to understand the role of the ligands and metal ions in biological systems.