<> "The repository administrator has not yet configured an RDF license."^^ . <> . . "Dinuclear copper(II) patellamide complexes: Studies on their potential hydrolase-like activities and in vivo stabilities"^^ . "The blue-green alga Prochloron produces and exports cyclic octapeptides (patellamides) to its obligate host, the ascidian Lissoclinum patella, in large quantities. Since the CuII concentration in the ascidians is a factor of 104 greater when compared to the surrounding sea water, previous studies on model CuII complexes with synthetic cyclic octapeptide derivatives were performed and revealed these complexes to be efficient phosphatase- and carboanhydrase-mimics. Their biological role, however, is so far unknown.\r\nWith the work presented in this thesis, the dependence of the phosphatase activity of dinuclear patellamide complexes on the side chain configuration as well as on the catalytic metal centre is explored. The results show that the complexes based on ligands with the natural R and S configuration of the patellamide-ligand backbone exhibit 3-5 times higher hydrolysis efficiencies as compared to complexes with ligands that exhibit 4S side chain configuration. Beyond that, the effect on phosphatase efficiency induced by the substitution of the catalytic metal centre CuII for ZnII was investigated. Since only one of the three ZnII patellamide complexes showed catalytic activity, a structural investigation was carried out. In addition to hydrolysis measurements this was accomplished by means of NMR, MS, ITC and a combined MM and QM study. The results indicate a similar binding behaviour of patellamides towards ZnII as shown for CuII, i.e. a coordination site spanned by two nitrogen atoms that are part of a heterocycle and a deprotonated amide nitrogen. Therefore, the lack of phosphatase activity might be caused by the small stability of these complexes under aqueous conditions, as used for the hydrolysis assay.\r\nIn addition, α- and β-glycosidase- as well as β-lactamase-like activity of the CuII patellamide complexes was examined. It was shown that the imidazole-based complexes act as hydrolases not only for phosphate ester cleavage at pH 7-8 but also for the hydrolysis of glycosidic bonds at alkaline conditions (pH 10). Moreover, β-lactamase-like activity was observed at pH 11.5 for one of the patellamide based complexes. Consequently, these results indicate the ability of the CuII complexes to act as very efficient, pH-dependent catalysts. Recent findings from BEHRENDT et al. pointed to a rapid fluctuation of the pH in close proximity to Prochloron depending on the irradiance. Therefore, the glycosidase and lactamase results could indicate the dinuclear CuII complexes to adopt different functions during day- and night-time, respectively.\r\nAbstract\r\nX\r\nAs a contribution towards the elucidation of the metabolic significance of the patellamide complexes, the formation of the complexes was investigated in vitro in buffer at pH 8.2 as well as in vivo. Therefore, a patellamide ligands with an appended reporter groups (RG) were prepared (see Figure 1).\r\nThe fluorescent tag Atto550 as well as the spin label Proxyl were chosen as the reporter groups. In vitro studies with H4pat-Atto550 indicate the formation of a CuII complex in buffer, however, results from EPR studies with the ligand H4pat-Proxyl and CuII could so far not verify this finding. In addition, a protocol for the uptake of patellamides by Prochloron was developed allowing the introduction of the ligand H4pat-RG into the cells. Results from flow cytometry as well as confocal microscopy support the formation of a CuII patellamide complex in vivo. In addition, preliminary in vivo hydrolysis measurements are presented.\r\nIn conclusion, the work presented contributes to an improved understanding of the hydrolase-like activities of the patellamide-based copper(II) complexes and gives a first insight on the stabilities of the complexes in Prochloron cells."^^ . "2017" . . . . . . . "Annika"^^ . "Eisenschmidt"^^ . "Annika Eisenschmidt"^^ . . . . . . "Dinuclear copper(II) patellamide complexes: Studies on their potential hydrolase-like activities and in vivo stabilities (PDF)"^^ . . . "Diss_Annika_fertig_1612.pdf"^^ . . . "Dinuclear copper(II) patellamide complexes: Studies on their potential hydrolase-like activities and in vivo stabilities (Other)"^^ . . . . . . "lightbox.jpg"^^ . . . "Dinuclear copper(II) patellamide complexes: Studies on their potential hydrolase-like activities and in vivo stabilities (Other)"^^ . . . . . . "preview.jpg"^^ . . . "Dinuclear copper(II) patellamide complexes: Studies on their potential hydrolase-like activities and in vivo stabilities (Other)"^^ . . . . . . "medium.jpg"^^ . . . "Dinuclear copper(II) patellamide complexes: Studies on their potential hydrolase-like activities and in vivo stabilities (Other)"^^ . . . . . . "small.jpg"^^ . . . "Dinuclear copper(II) patellamide complexes: Studies on their potential hydrolase-like activities and in vivo stabilities (Other)"^^ . . . . . . "indexcodes.txt"^^ . . "HTML Summary of #22595 \n\nDinuclear copper(II) patellamide complexes: Studies on their potential hydrolase-like activities and in vivo stabilities\n\n" . "text/html" . . . "540 Chemie"@de . "540 Chemistry and allied sciences"@en . .