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.

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.

An easy-to-prepare series of electroactive poly(amido amine) (PAMAM)-based dendrimers of generations G0 to G2 having mannopyranosylferrocenyl moieties in the periphery to detect carbohydrate-protein interactions is reported. The synthesis involved the functionalization of the PAMAM surface with azidomethylferrocenyl groups and subsequent coupling of mannoside units by the Cu(I)-catalyzed Huisgen reaction. The binding affinity of the series of electroactive glycodendrimers was studied by isothermal titration calorimetry (ITC) and differential pulse voltammetry (DPV). Upon complexation of the glycodendrimers conjugates with prototypical concanavalin A (Con A), voltammograms showed a decrease of the peak current. Such dendrimers showed a notable improvement of redox sensing abilities toward Con A when compared with mono- and divalent analogues, based on both the glycoside multivalent and ferrocene dendritic effects.

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The synthesis of a series of β‐cyclodextrin (CD) dimers in which the two macrocycle units are linked by rigid‐rod phenylene‐ethynylene tethers of different length and shape through the cyclodextrin secondary sides is reported. The synthesis involves Sonogashira coupling reactions for construction of the tethers and final grafting of the CD units by click chemistry. The self‐aggregation of the synthesized CD dimers in aqueous medium was investigated by fluorescence spectroscopy, isothermal titration calorimetry and dynamic light scattering. Rigid‐rod‐tethered cyclodextrin dimers formed polydisperse nanoparticles of 240 to 480 nm in water solution depending on the tether shape, and exhibited fluorescence. The binding and fluorescence sensing abilities of the CD dimers toward sodium cholate and deoxycholate were studied. As a result, the newly synthesized rigid‐rod‐tethered cyclodextrin dimers proved to be very sensitive fluorescent chemosensors. A new cyclodextrin‐based ratiometric fluorescence probe has thus been developed for the detection of bile salts such as sodium cholate and deoxycholate.