Ferrocene with a beta-cyclodextrin unit bound to one or both cyclopentadienyl rings through the secondary face were conveniently synthesized by regiospecific copper(I)-catalyzed cycloaddition of 2-O-propargyl-beta-cyclodextrin to azidomethyl or bis(azidomethyl)ferrocene. The supramolecular behavior of the synthesized conjugates in both the absence and presence of bile salts (sodium cholate, deoxycholate, and chenodeoxycholate) was studied by using electrochemical methods (cyclic and differential pulse voltammetry), isothermal titration calorimetry, and NMR spectroscopy (PGSE, CPMG, and 2D-ROESY). These techniques allowed the determination of stability constants, mode of inclusion, and diffusion coefficients for complexes formed with the neutral and, in some cases, the oxidized states of the ferrocenyl conjugates. It was found that the ferrocenyl conjugate with one beta-cyclodextrin unit forms a redox-controllable head-to-head homodimer in aqueous solution. The ferrocene-bis(beta-cyclodextrin) conjugate is present in two distinguishable forms in aqueous solution, each one having a different half-wave oxidation potential for the oxidation of the ferrocene. By contrast, only one distinguishable form for the oxidized state of the ferrocene-beta-cyclodextrin conjugate is detectable. The redox-sensing abilities of the synthesized conjugates towards the bile salts were evaluated based on the observed guest-induced changes in both the half-wave potential and the current peak intensity of the electroactive moiety.

We report two methods that have allowed the attachment of glucose, mannose and lactose to one or both of the cyclopentadienyl rings of ferrocene. The resulting ferrocene-carbohydrate conjugates were synthesised by the reaction of thioglycosides with ferrocenemethanol and 1,1'-ferrocenedimethanol in acidic media. A second method based on the regiospecific copper(I)-catalysed cycloaddition of propargyl glycoside, azidomethyl and bis(azidomethyl)ferrocene as well as azidoethyl glycoside and ethynylferrocene was also used and led to the synthesis of 1,2,3-triazole-containing glycoconjugates. The electrochemical behaviour of the synthesised glycoconjugates was investigated. In addition, their binding interactions with beta-cyclodextrin were studied by means of NMR spectroscopy, isothermal titration calorimetry, and cyclic and differential pulse voltammetric experiments. These techniques allowed the determination of the thermodynamic parameters of the complexes, the stability constants for the complexes formed with both the neutral and the oxidised states of the ferrocenyl glycoconjugates, the mode of inclusion and the diffusion coefficients for both the glycoconjugates and the complexes.

Three novel gold nanoparticles containing multiple long, flexible linkers decorated with lactose, β-cyclodextrin, and both simultaneously have been prepared. The interaction of such nanoparticles with β-d-galactose-recognizing lectins peanut agglutinin (PNA) and human galectin-3 (Gal-3) was demonstrated by UV-vis studies. Gal-3 is well-known to be overexpressed in several human tumors and can act as a biorecognizable target. This technique also allowed us to estimate their loading capability toward the anticancer drug methotrexate (MTX). Both results make these glyconanoparticles potential site-specific delivery systems for anticancer drugs.

Over the last decade an increasing number of studies have been published reporting on the inhibitory potency or selectivity that several types of ligands show against human galectin-3 (hGal-3). The reason for this interest lies in the many important roles galectins play both in intra and extra-cellular functions. Among galectins, galectin-3 stands out because it is the only known member of its subfamily in mammals, is small and monomeric but capable of aggregating, and is known to be involved in a large number of disease processes, from cancer to heart failure. These characteristics and roles make hGal-3 an ideal target for drugs. Since it binds β-galactosides, like the rest of the galectin family of proteins, the search and design of potent and at the same time selective inhibitors for it is not an easy task. Herein we discuss the chemical features of the most potent inhibitors described so far, as well as the structural basis of their exhibited selectivity, in order to shed light on the rational design of drugs against this target.

The effect of the Y108V mutation of human glutathione S-transferase P1-1 (hGST P1-1) on the binding of the diuretic drug ethacrynic acid (EA) and its glutathione conjugate (EASG) was investigated by calorimetric, spectrofluorimetric, and crystallographic studies. The mutation Tyr 108 fi Val resulted in a 3D-structure very similar to the wild type (wt) enzyme, where both the hydrophobic ligand binding site (H-site) and glutathione binding site (G-site) are unchanged except for the mutation itself. However, due to a slight increase in the hydrophobicity of the H-site, as a consequence of the mutation, an increase in the entropy was observed. The Y108V mutation does not affect the affinity of EASG for the enzyme, which has a higher affinity (K d~0 .5 lM) when compared with those of the parent compounds, K EA d~1 3 lM, K GSH d~2 5 lM. The EA moiety of the conjugate binds in the H-site of Y108V mutant in a fashion completely different to those observed in the crystal structures of the EA or EASG wt complex structures. We further demonstrate that the DC p values of binding can also be correlated with the potential stacking interactions between Additional Supporting Information may be found in the online version of this article.Abbreviations: DMSO, dimethylsulfoxide; DSC, differential scanning calorimetry; DTT, dithiothreitol; EA, ethacrynic acid; EACys, ethacrynic-cysteine conjugate; EAME, ethacrynic-mercaptoethanol conjugate; EASG, ethacrynic-glutathione conjugate; GST, glutathione transferase; HEPES, N-(2-hydroxyethyl)-piperazine-N'-2-ethanesulfonic acid; hGST P1-1, human glutathione transferase P1-1; ITC, isothermal titration calorimetry; MES, 2-morpholinoethanesulfonic acid; MPD, 2-methyl-2,4-pentanediol; wt, wild type.Indalecio Quesada-Soriano and Lorien J. Parker contributed equally to this work.The coordinates for the structures of the Y108V apo, EA and EASG complex are deposited with the Protein Databank (http:// rcsg.org/pdb/) with the entry codes 3HJM, 3HKR, and 3HJO, respectively. ligand and residues located in the binding sites as predicted from crystal structures. Moreover, the mutation does not significantly affect the global stability of the enzyme. Our results demonstrate that calorimetric measurements maybe useful in determining the preference of binding (the binding mode) for a drug to a specific site of the enzyme, even in the absence of structural information.