Zsuzsa Majer
Eötvös Loránd University Budapest, Organic Chemistry, Faculty Member
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NGR-peptides that recognize the CD13 receptors on tumor neovasculature are of high interest, in particular due to their potential applications in drug targeting. Here we report the synthesis and structure analysis of novel thioether... more
NGR-peptides that recognize the CD13 receptors on tumor neovasculature are of high interest, in particular due to their potential applications in drug targeting. Here we report the synthesis and structure analysis of novel thioether bond-linked cyclic NGR-peptides. Our results show that their chemo-stability (resistance against spontaneous decomposition forming isoAsp and Asp derivatives) strongly depends both on sample handling conditions and structural properties. A significant correlation was found between the chemo-stability and structural measures, such as NHGly…COAsn-sc distances. The side chain orientation of Asn is a key determining factor; if turned away from HNGly, the chemo-stability increases. Structure stabilizing factors (e.g. H-bond(s)) lower their internal dynamics and thus, biomolecules become even more resistant against spontaneous decomposition. The effect of cyclic NGR-peptides on cell adhesion was examined on A2058 melanoma cell lines. It was found that some of ...
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ABSTRACT In vitro antitumor efficacy of several dinuclear bridging and one chelate structure dirhodium(II) complexes of N-protected phenylalanine derivatives were tested on HT-29 cells. The following synthesized and previously... more
ABSTRACT In vitro antitumor efficacy of several dinuclear bridging and one chelate structure dirhodium(II) complexes of N-protected phenylalanine derivatives were tested on HT-29 cells. The following synthesized and previously characterized complexes were applied in the present work: Rh2(OAc)4 -n(O-Phe-Z)n (n = 1-4, -O-Phe-Z = N-benzyloxycarbonyl-L-phenyalaninate), Rh2(OAc)4 -n(O-Phe-Ac)n (n = 1-4, -O-Phe-Ac = N-acetyl-L-phenylalaninate), Rh2(OAc)2(N-Me-D-Phe-O)2 corresponding to N-methyl-D-phenylalaninate as well as Rh2(OAc)4 (-OAc = acetate). Depending on the complex ligand type and its coordination number, the intracellular rhodium (Rh) content determined by total reflection X-ray fluorescence (TXRF) spectrometry in the HT-29 cells varied between 25 and 2500 ng / 106 cells. In vitro cytotoxicity and cytostatic evaluations of the compounds on HT-29 human cell culture were performed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) assay. Compared to Rh2(OAc)4, the Rh compounds containing one or two -O-Phe-Z moieties proved to be the most effective on the HT-29 cells. Moreover, synchrotron radiation TXRF - X-ray absorption near edge structure measurements suggested a change of the molecular symmetry of the dirhodium(II) center for the moderately in vitro cytotoxic, lipophilic L-phenylalanine derivative complexes, characterized also by low ligand exchange rate when they were studied on HT-29 cells.
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This paper reports CD spectroscopic studies on acridino-18-crown-6 ligands (RR)-2 and 2a (see Figure 1), and their complexes with the enantiomers of alpha-naphthyl)ethylamine hydrogenperchlorate (1-NEA), 1-phenylethylamine... more
This paper reports CD spectroscopic studies on acridino-18-crown-6 ligands (RR)-2 and 2a (see Figure 1), and their complexes with the enantiomers of alpha-naphthyl)ethylamine hydrogenperchlorate (1-NEA), 1-phenylethylamine hydrogenperchlorate (PEA) and alpha-2-naphthyl)ethylamine hydrogenperchlorate (2-NEA), and also with the achiral guests (1-naphthyl)methylamine hydrogenperchlorate (1-NMA), benzylamine hydrogenperchlorate (BA), methylamine hydrogenperchlorate (MA) and 1-methylnaphthalene (1-MN). The general feature of the CD spectra of complexes of (RR)-2 with MA, BA, (R)- and (S)-PEA is the replacement of the oppositely signed 1Bb doublet of the host by one positive band near 265 nm. The CD spectra of the heterochiral and homochiral complexes of phenazino and acridino hosts (R,R)-1, 1a, (R,R)-2 and 2a with (R)- and (S)-1-NEA and 1-NMA are governed by exciton interaction. Surprisingly, the heterochial [(R,R)/(S)] complexes of the structural isomeric 2-NEA gave rise to a positive couplet in contrast to the negative couplet measured in the spectrum of the heterochiral [(R,R)/(S)] complexes of 1-NEA.
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This paper reports on the synthesis and chiroptical spectroscopic characterization of Rh2(OAc)4−n(O-Phe-Z)n (n=1–4, abbreviated as Rh2L1, Rh2L2, Rh2L3 and Rh2L4) complexes. Mixtures of these complexes were prepared in MeCN and CHCl3... more
This paper reports on the synthesis and chiroptical spectroscopic characterization of Rh2(OAc)4−n(O-Phe-Z)n (n=1–4, abbreviated as Rh2L1, Rh2L2, Rh2L3 and Rh2L4) complexes. Mixtures of these complexes were prepared in MeCN and CHCl3 solvents from a Rh2(OAc)4 core complex and the chiral N-protected amino acid N-benzyloxycarbonyl-l-phenylalanine (Z-Phe-OH). The components of the in situ mixture of complexes proved to be stable enough to
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... CD spectra were recorded on a Roussel-Jouan Dichrograph Mark III instrument (Jobin-Yvon) oper-ated by a Kontron PSI 80 D conputer system. Spectrograde solvents (Uvasol, E.Merck, Darmstadt) were used. ... 17. M. Kajt&r, M.... more
... CD spectra were recorded on a Roussel-Jouan Dichrograph Mark III instrument (Jobin-Yvon) oper-ated by a Kontron PSI 80 D conputer system. Spectrograde solvents (Uvasol, E.Merck, Darmstadt) were used. ... 17. M. Kajt&r, M. Hollosi, J. Kajtar, Zs. ...
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Research Interests: Thermodynamics, Protein Folding, Kinetics, Protein Science, Biological Sciences, and 16 moreMutation, Circular Dichroism, Differential scanning calorimetry, Mathematical Sciences, Animals, Temperature, Long Range, Proteins, Tryptophan, Milk, Goats, Phenylalanine, Protein Conformation, Amino Acid Substitution Rates, Protein Denaturation, and Conformational Change
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... by Amir Avdagita), Andreja Lesac"). Zsuzsa Majerb), Miklos Hollosi '). and Vitomir sunjib")* ") Ruzter BoSkovii. ... 7 80 83.0 x5.7 195 - 15 49.2 33.6 7 40 64.3 68.5 50 30 48.4 10.2 Table 3. Temperuture-Dependnt... more
... by Amir Avdagita), Andreja Lesac"). Zsuzsa Majerb), Miklos Hollosi '). and Vitomir sunjib")* ") Ruzter BoSkovii. ... 7 80 83.0 x5.7 195 - 15 49.2 33.6 7 40 64.3 68.5 50 30 48.4 10.2 Table 3. Temperuture-Dependnt Acel~lu/ion of Prochirul 16 E \p"' Lipase [mg] Time [h] Temp. ...
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Research Interests: Thermodynamics, Calcium, Biophysical Chemistry, Biological Sciences, Circular Dichroism, and 20 moreAnimals, Physical sciences, Temperature, Molten Globule, Milk, Goats, CHEMICAL SCIENCES, Cattle, Heat Capacity, Protein Secondary Structure Prediction, Amino Acid Profile, Isothermal Titration Calorimetry, Protein Conformation, Calorimetry, Amino Acid Sequence, Charge Distribution, Binding Site, Conformational Change, Thermodynamic Parameter, and Molecular Sequence Data
Research Interests: Organic Chemistry, FTIR spectroscopy, Calcium, FTIR, Models, and 15 moreCircular Dichroism, Cyclic peptides, Spectrum, Liquid Chromatography / Electrospray Ionization Mass Spectrometry, Time Dependent, Fourier transform infrared spectroscopy, Infrared spectra, Amino Acid Profile, Bioorganic and medicinal Chemistry, Amino Acid Sequence, Infrared Spectrometry, Binding Site, Fourier Transformation, Fourier transform infrared, and Molecular Sequence Data
Research Interests: Kinetics, Calcium, Humans, Circular Dichroism, Collagen, and 11 moreCyclic peptides, Enzyme, Secondary Structure, Protein Secondary Structure Prediction, Fourier transform infrared spectroscopy, Substrate Specificity, Enzyme activity, Amino Acid Sequence, Recombinant Proteins, Biochemistry and cell biology, and Matrix Metalloproteinase
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Research Interests: Artificial Intelligence, Computational Biology, Principal Component Analysis, Software, Humans, and 11 moreCircular Dichroism, Drug Design, Quantitative Structure Activity Relationship, Support vector machine, Amino Acids, CD Spectroscopy, Protein Conformation, Virtual Library, Antitumor Activity, Adamantane, and Antineoplastic Agents
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Mono- and dithionated N-acyl amino acid and dipeptide N'-methylamides were synthesized using Lawesson's reagent and S-thioacetyl thioglycolic acid. The conformation of the thionated models was characterized by IR, 13C, and... more
Mono- and dithionated N-acyl amino acid and dipeptide N'-methylamides were synthesized using Lawesson's reagent and S-thioacetyl thioglycolic acid. The conformation of the thionated models was characterized by IR, 13C, and 1H NMR spectroscopy, including NOE experiments. The formation of -C = S...H-N-C = X (X = O or S) intramolecular H-bonds of the type 2----2, 1----3 and 1----4 was evidenced by the characteristic shifts of the IR stretching frequencies of the NH group. Act-Pro-NHCH3(4) and Act-Prot-NHCH3(5) were found to be present as mixtures of rotational isomers about the CS-N bond. 13C chemical shifts of the gamma- and beta-carbons of the proline ring elucidated the conformation (Z or E) of the tertiary thioamide group. Our results suggest that the conformation of thiopeptides is determined by two factors: 1) the H-bond donating and accepting ability of the thioamide group and 2) the repulsion between the thiocarbonyl sulfur atom and the side chain groups of the neighbouring amino acid residues.
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Circular dichroism and Fourier-transform infrared spectroscopies were used to compare the conformational mobility of 13-mer peptides covering the 317-329 region of the envelope protein hemagglutinin of human influenza A virus subtypes H1,... more
Circular dichroism and Fourier-transform infrared spectroscopies were used to compare the conformational mobility of 13-mer peptides covering the 317-329 region of the envelope protein hemagglutinin of human influenza A virus subtypes H1, H2 and H3 with that of their truncated deca- and nonapeptide analogs. These peptides were demonstrated to bind to the murine I-Ed major histocompatibility complex encoded class II and human HLA-B*2705 class I molecules. Despite the amino acid substitutions in the three 13-mer subtype sequences, no significant differences in the conformational properties could be shown. Deletion of the N-terminal three residues resulted in a shift to an increased alpha-helical conformer population in the 317-329 H1 peptide and the breakage of the 3(10) or weakly H-bonded (nascent) alpha-helix in the H2 and H3 peptides. The conformational change observed upon deletion did not influence the efficiency of I-Ed peptide interaction, however, the C-terminal Arg had a beneficial effect both on MHC class II and class I binding without causing any remarkable change in solution conformation.