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Bartok A, Fehér K, Bodor A, Rákosi K, Tóth GK, Kövér KE, Panyi G, Varga Z. An engineered scorpion toxin analogue with improved Kv1.3 selectivity displays reduced conformational flexibility. Sci Rep 2015; 5:18397. [PMID: 26689143 PMCID: PMC4686915 DOI: 10.1038/srep18397] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 11/04/2015] [Indexed: 12/11/2022] Open
Abstract
The voltage-gated Kv1.3 K+ channel plays a key role in the activation of T lymphocytes. Kv1.3 blockers selectively suppress immune responses mediated by effector memory T cells, which indicates the great potential of selective Kv1.3 inhibitors in the therapy of certain autoimmune diseases. Anuroctoxin (AnTx), a 35-amino-acid scorpion toxin is a high affinity blocker of Kv1.3, but also blocks Kv1.2 with similar potency. We designed and produced three AnTx variants: ([F32T]-AnTx, [N17A]-AnTx, [N17A/F32T]-AnTx) using solid-phase synthesis with the goal of improving the selectivity of the toxin for Kv1.3 over Kv1.2 while keeping the high affinity for Kv1.3. We used the patch-clamp technique to determine the blocking potency of the synthetic toxins on hKv1.3, mKv1.1, hKv1.2 and hKCa3.1 channels. Of the three variants [N17A/F32T]-AnTx maintained the high affinity of the natural peptide for Kv1.3 but became more than 16000-fold selective over Kv1.2. NMR data and molecular dynamics simulations suggest that the more rigid structure with restricted conformational space of the double substituted toxin compared to the flexible wild-type one is an important determinant of toxin selectivity. Our results provide the foundation for the possibility of the production and future therapeutic application of additional, even more selective toxins targeting various ion channels.
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Gógl G, Alexa A, Kiss B, Katona G, Kovács M, Bodor A, Reményi A, Nyitray L. Structural Basis of Ribosomal S6 Kinase 1 (RSK1) Inhibition by S100B Protein: MODULATION OF THE EXTRACELLULAR SIGNAL-REGULATED KINASE (ERK) SIGNALING CASCADE IN A CALCIUM-DEPENDENT WAY. J Biol Chem 2015; 291:11-27. [PMID: 26527685 DOI: 10.1074/jbc.m115.684928] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Indexed: 12/31/2022] Open
Abstract
Mitogen-activated protein kinases (MAPK) promote MAPK-activated protein kinase activation. In the MAPK pathway responsible for cell growth, ERK2 initiates the first phosphorylation event on RSK1, which is inhibited by Ca(2+)-binding S100 proteins in malignant melanomas. Here, we present a detailed in vitro biochemical and structural characterization of the S100B-RSK1 interaction. The Ca(2+)-dependent binding of S100B to the calcium/calmodulin-dependent protein kinase (CaMK)-type domain of RSK1 is reminiscent of the better known binding of calmodulin to CaMKII. Although S100B-RSK1 and the calmodulin-CAMKII system are clearly distinct functionally, they demonstrate how unrelated intracellular Ca(2+)-binding proteins could influence the activity of the CaMK domain-containing protein kinases. Our crystallographic, small angle x-ray scattering, and NMR analysis revealed that S100B forms a "fuzzy" complex with RSK1 peptide ligands. Based on fast-kinetics experiments, we conclude that the binding involves both conformation selection and induced fit steps. Knowledge of the structural basis of this interaction could facilitate therapeutic targeting of melanomas.
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Katona G, Duelli A, Kiss B, Lundholm I, Bodor A, Petoukhov M, Svergun D, Nyitray L. Conformational regulation of the C‐terminal random coil in S100A4 by Ca2+ ions. FASEB J 2015. [DOI: 10.1096/fasebj.29.1_supplement.563.5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Bodor A, Kövér KE, Mäler L. Membrane interactions in small fast-tumbling bicelles as studied by 31P NMR. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1848:760-6. [PMID: 25497765 DOI: 10.1016/j.bbamem.2014.12.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Revised: 11/11/2014] [Accepted: 12/01/2014] [Indexed: 01/02/2023]
Abstract
Small fast-tumbling bicelles are ideal for studies of membrane interactions at molecular level; they allow analysis of lipid properties using solution-state NMR. In the present study we used 31P NMR relaxation to obtain detailed information on lipid head-group dynamics. We explored the effect of two topologically different membrane-interacting peptides on bicelles containing either dimyristoylphosphocholine (DMPC), or a mixture of DMPC and dimyristoylphosphoglycerol (DMPG), and dihexanoylphosphocholine (DHPC). KALP21 is a model transmembrane peptide, designed to span a DMPC bilayer and dynorphin B is a membrane surface active neuropeptide. KALP21 causes significant increase in bicelle size, as evidenced by both dynamic light scattering and 31P T2 relaxation measurements. The effect of dynorphin B on bicelle size is more modest, although significant effects on T2 relaxation are observed at higher temperatures. A comparison of 31P T1 values for the lipids with and without the peptides showed that dynorphin B has a greater effect on lipid head-group dynamics than KALP21, especially at elevated temperatures. From the field-dependence of T1 relaxation data, a correlation time describing the overall lipid motion was derived. Results indicate that the positively charged dynorphin B decreases the mobility of the lipid molecules--in particular for the negatively charged DMPG--while KALP21 has a more modest influence. Our results demonstrate that while a transmembrane peptide has severe effects on overall bilayer properties, the surface bound peptide has a more dramatic effect in reducing lipid head-group mobility. These observations may be of general importance for understanding peptide-membrane interactions.
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Bodor A, Radnai L, Hetényi C, Rapali P, Láng A, Kövér KE, Perczel A, Wahlgren WY, Katona G, Nyitray L. DYNLL2 dynein light chain binds to an extended linear motif of myosin 5a tail that has structural plasticity. Biochemistry 2014; 53:7107-22. [PMID: 25312846 DOI: 10.1021/bi500574z] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
LC8 dynein light chains (DYNLL) are conserved homodimeric eukaryotic hub proteins that participate in diverse cellular processes. Among the binding partners of DYNLL2, myosin 5a (myo5a) is a motor protein involved in cargo transport. Here we provide a profound characterization of the DYNLL2 binding motif of myo5a in free and DYNLL2-bound form by using nuclear magnetic resonance spectroscopy, X-ray crystallography, and molecular dynamics simulations. In the free form, the DYNLL2 binding region, located in an intrinsically disordered domain of the myo5a tail, has a nascent helical character. The motif becomes structured and folds into a β-strand upon binding to DYNLL2. Despite differences of the myo5a sequence from the consensus binding motif, one peptide is accommodated in each of the parallel DYNLL2 binding grooves, as for all other known partners. Interestingly, while the core motif shows a similar interaction pattern in the binding groove as seen in other complexes, the flanking residues make several additional contacts, thereby lengthening the binding motif. The N-terminal extension folds back and partially blocks the free edge of the β-sheet formed by the binding motif itself. The C-terminal extension contacts the dimer interface and interacts with symmetry-related residues of the second myo5a peptide. The involvement of flanking residues of the core binding site of myo5a could modify the quaternary structure of the full-length myo5a and affect its biological functions. Our results deepen the knowledge of the diverse partner recognition of DYNLL proteins and provide an example of a Janus-faced linear motif.
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Duelli A, Kiss B, Lundholm I, Bodor A, Petoukhov MV, Svergun DI, Nyitray L, Katona G. The C-terminal random coil region tunes the Ca²⁺-binding affinity of S100A4 through conformational activation. PLoS One 2014; 9:e97654. [PMID: 24830809 PMCID: PMC4022583 DOI: 10.1371/journal.pone.0097654] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Accepted: 04/22/2014] [Indexed: 11/19/2022] Open
Abstract
S100A4 interacts with many binding partners upon Ca2+ activation and is strongly associated with increased metastasis formation. In order to understand the role of the C-terminal random coil for the protein function we examined how small angle X-ray scattering of the wild-type S100A4 and its C-terminal deletion mutant (residues 1–88, Δ13) changes upon Ca2+ binding. We found that the scattering intensity of wild-type S100A4 changes substantially in the 0.15–0.25 Å−1 q-range whereas a similar change is not visible in the C-terminus deleted mutant. Ensemble optimization SAXS modeling indicates that the entire C-terminus is extended when Ca2+ is bound. Pulsed field gradient NMR measurements provide further support as the hydrodynamic radius in the wild-type protein increases upon Ca2+ binding while the radius of Δ13 mutant does not change. Molecular dynamics simulations provide a rational explanation of the structural transition: the positively charged C-terminal residues associate with the negatively charged residues of the Ca2+-free EF-hands and these interactions loosen up considerably upon Ca2+-binding. As a consequence the Δ13 mutant has increased Ca2+ affinity and is constantly loaded at Ca2+ concentration ranges typically present in cells. The activation of the entire C-terminal random coil may play a role in mediating interaction with selected partner proteins of S100A4.
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Barabás O, Németh V, Bodor A, Perczel A, Rosta E, Kele Z, Zagyva I, Szabadka Z, Grolmusz VI, Wilmanns M, Vértessy BG. Catalytic mechanism of α-phosphate attack in dUTPase is revealed by X-ray crystallographic snapshots of distinct intermediates, 31P-NMR spectroscopy and reaction path modelling. Nucleic Acids Res 2013; 41:10542-55. [PMID: 23982515 PMCID: PMC3905902 DOI: 10.1093/nar/gkt756] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2013] [Revised: 07/29/2013] [Accepted: 07/31/2013] [Indexed: 12/26/2022] Open
Abstract
Enzymatic synthesis and hydrolysis of nucleoside phosphate compounds play a key role in various biological pathways, like signal transduction, DNA synthesis and metabolism. Although these processes have been studied extensively, numerous key issues regarding the chemical pathway and atomic movements remain open for many enzymatic reactions. Here, using the Mason-Pfizer monkey retrovirus dUTPase, we study the dUTPase-catalyzed hydrolysis of dUTP, an incorrect DNA building block, to elaborate the mechanistic details at high resolution. Combining mass spectrometry analysis of the dUTPase-catalyzed reaction carried out in and quantum mechanics/molecular mechanics (QM/MM) simulation, we show that the nucleophilic attack occurs at the α-phosphate site. Phosphorus-31 NMR spectroscopy ((31)P-NMR) analysis confirms the site of attack and shows the capability of dUTPase to cleave the dUTP analogue α,β-imido-dUTP, containing the imido linkage usually regarded to be non-hydrolyzable. We present numerous X-ray crystal structures of distinct dUTPase and nucleoside phosphate complexes, which report on the progress of the chemical reaction along the reaction coordinate. The presently used combination of diverse structural methods reveals details of the nucleophilic attack and identifies a novel enzyme-product complex structure.
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Kali G, Szesztay M, Bodor A, Iván B. Star and Hyperbranched Polyisobutylenes via Terminally Reactive Polyisobutylene-Polystyrene Block Copolymers. ACTA ACUST UNITED AC 2013. [DOI: 10.1002/masy.201100116] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Kiss K, Holczbauer T, Czugler M, Sohár P, Bodor A, Csámpai A. Synthesis, IR-, NMR-, DFT- and X-ray analysis of novel C2-chiral diferrocenyl–salen complexes. J Organomet Chem 2012. [DOI: 10.1016/j.jorganchem.2012.01.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Csapó Á, Bodor A, Rábai J. Hiyama coupling reaction of fluorous alkenyl-fluorosilanes: Scope and mechanistic considerations. J Fluor Chem 2012. [DOI: 10.1016/j.jfluchem.2012.03.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Zotter Á, Oláh J, Hlavanda E, Bodor A, Perczel A, Szigeti K, Fidy J, Ovádi J. Zn²+-induced rearrangement of the disordered TPPP/p25 affects its microtubule assembly and GTPase activity. Biochemistry 2011; 50:9568-78. [PMID: 21995432 DOI: 10.1021/bi201447w] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Tubulin polymerization promoting protein/p25 (TPPP/p25) modulates the dynamics and stability of the microtubule system and plays crucial role in the myelination of oligodendrocytes. Here we showed by CD, fluorescence, and NMR spectroscopies that Zn(2+) is the first ligand that induces considerable rearrangement of the disordered TPPP/p25. Zinc finger motif (His(2)Cys(2)) (His(61)-Cys(83)) was identified within the flexible region of TPPP/p25 straddled by extended unstructured N- and C-terminal regions. The specific binding of the Zn(2+) to TPPP/p25 induced the formation of molten globule but not that of a well-defined tertiary structure. The Zn(2+)-induced partially folded structure accommodating the zinc binding motif is localized at the single Trp(76)-containing region as demonstrated by fluorescence resonance energy transfer and quenching experiments. We showed that the Zn(2+)-induced change in the TPPP/p25 structure modified its interaction with tubulin and GTP coupled with functional consequences: the TPPP/p25-promoted tubulin polymerization was increased while the TPPP/p25-catalyzed GTPase activity was decreased as detected by turbidimetry and by malachite green phosphate release/(31)P NMR assays, respectively. The finding that the Zn(2+) of the bivalent cations can uniquely influence physiological relavant interactions significantly contributes to our understanding of the role of Zn(2+)-related TPPP/p25 processes in the differentiation/myelination of oligodendrocytes possessing a high-affinity Zn(2+) uptake mechanism.
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Szolnoki Z, Kondacs A, Mandi Y, Bodor A, Somogyvari F. A homozygous genetic variant of mitochondrial uncoupling protein 4 affects the occurrence of leukoaraiosis. Acta Neurol Scand 2011; 123:352-7. [PMID: 20545631 DOI: 10.1111/j.1600-0404.2010.01391.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
OBJECTIVES We hypothesized that an appropriate balance of the mitochondrial energy production is essential in the maintenance of the glia cells in the brain. The aim of this study was to examine the roles of the rs10807344 and rs2270450 genetic variants of mitochondrial uncoupling protein 4 in the development of vascular demyelinization of the white matter of the brain, referred to as leukoaraiosis (LA). The mUCPs are presumed to be of great importance in the regulation of the mitochondrial membrane potential (MMP) and the cellular energy metabolism. MATERIALS AND METHODS An analysis was performed on the clinical and genetic data on 401 LA patients without infarction and on 451 neuroimaging alteration-free subjects. After univariate statistical approaches, logistic regression models were also used to adjust differences in significant clinical factors between the patients and controls. RESULTS The rs10807344 CC genotype proved to exert a protective effect on the occurrence of LA (neuroimaging alteration-free controls: 57.7%, LA group: 44.9%, P < 0.0002; adjusted OR: 0.41, 95% CI: 0.2-0.68, P < 0.005). CONCLUSION The present findings indirectly raise the possibility that a shift or imbalance in the finely regulated MMP may play a role in the development of LA.
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Zotter A, Bodor A, Oláh J, Hlavanda E, Orosz F, Perczel A, Ovádi J. Disordered TPPP/p25 binds GTP and displays Mg2+-dependent GTPase activity. FEBS Lett 2011; 585:803-8. [PMID: 21316364 DOI: 10.1016/j.febslet.2011.02.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2010] [Revised: 02/01/2011] [Accepted: 02/04/2011] [Indexed: 10/18/2022]
Abstract
The disordered Tubulin Polymerization Promoting Protein/p25 (TPPP/p25) modulates the dynamics and stability of the microtubule system and plays a crucial role in differentiation of oligodendrocytes. Here we first demonstrated by multinuclear NMR that the extended disordered segments are localized at the N- and C-terminals straddling a flexible region. We showed by affinity chromatography, fluorescence spectroscopy and circular dichroism that GTP binds to TPPP/p25 likely within the flexible region; neither positions nor intensities of the peaks in the assigned terminals were affected by GTP. In addition, we demonstrated that TPPP/p25 specifically hydrolyses GTP in an Mg(2+)-dependent manner. The GTPase activity is comparable with the intrinsic activities of small G proteins suggesting its potential role in multiple physiological processes.
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Szőllősi E, Bokor M, Bodor A, Perczel A, Klement E, Medzihradszky KF, Tompa K, Tompa P. Intrinsic Structural Disorder of DF31, a Drosophila Protein of Chromatin Decondensation and Remodeling Activities. J Proteome Res 2008; 7:2291-9. [DOI: 10.1021/pr700720c] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Manea M, Kalászi A, Mezo G, Horváti K, Bodor A, Horváth A, Farkas O, Perczel A, Przybylski M, Hudecz F. Antibody recognition and conformational flexibility of a plaque-specific beta-amyloid epitope modulated by non-native peptide flanking regions. J Med Chem 2008; 51:1150-61. [PMID: 18284185 DOI: 10.1021/jm070196e] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Here we report on the synthesis, antibody binding, and QSAR studies of a series of linear and cyclic peptides containing a beta-amyloid plaque-specific epitope (Abeta(4-10); FRHDSGY). In these constructs, two or three alpha- l-Ala, alpha- d-Ala, or beta-Ala residues were introduced at both N- and C-termini of the epitope as non-native flanking sequences. Cyclization of the linear Abeta(4-10) epitope peptide resulted in reduced antibody binding. However, the antibody binding could be fully compensated by insertion of alanine flanks into the corresponding cyclic peptides. These results indicate that the modification of a beta-amyloid plaque-specific epitope by combination of cyclization and flanking sequences could generate highly antigenic peptides compared to the native sequence. A novel 3D QSAR method, which explicitly handles conformational flexibility, was developed for the case of such molecular libraries. This method led to the prediction of the binding conformation for the common FRHDSGY sequence.
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Gyimesi M, Kintses B, Bodor A, Perczel A, Fischer S, Bagshaw CR, Málnási-Csizmadia A. The mechanism of the reverse recovery step, phosphate release, and actin activation of Dictyostelium myosin II. J Biol Chem 2008; 283:8153-63. [PMID: 18211892 DOI: 10.1074/jbc.m708863200] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The rate-limiting step of the myosin basal ATPase (i.e. in absence of actin) is assumed to be a post-hydrolysis swinging of the lever arm (reverse recovery step), that limits the subsequent rapid product release steps. However, direct experimental evidence for this assignment is lacking. To investigate the binding and the release of ADP and phosphate independently from the lever arm motion, two single tryptophan-containing motor domains of Dictyostelium myosin II were used. The single tryptophans of the W129+ and W501+ constructs are located at the entrance of the nucleotide binding pocket and near the lever arm, respectively. Kinetic experiments show that the rate-limiting step in the basal ATPase cycle is indeed the reverse recovery step, which is a slow equilibrium step (k(forward) = 0.05 s(-1), k(reverse) = 0.15 s(-1)) that precedes the phosphate release step. Actin directly activates the reverse recovery step, which becomes practically irreversible in the actin-bound form, triggering the power stroke. Even at low actin concentrations the power stroke occurs in the actin-attached states despite the low actin affinity of myosin in the pre-power stroke conformation.
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Fábos V, Lantos D, Bodor A, Bálint AM, Mika LT, Sielcken OE, Cuiper A, Horváth IT. Epsilon-caprolactamium hydrogen sulfate: an ionic liquid used for decades in the large-scale production of epsilon-caprolactam. CHEMSUSCHEM 2008; 1:189-192. [PMID: 18605204 DOI: 10.1002/cssc.200700135] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
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Kali G, Szesztay M, Bodor A, Iván B. A New Synthetic Method for the Preparation of Star-Shaped Polyisobutylene with Hyperbranched Polystyrene Core. MACROMOL CHEM PHYS 2007. [DOI: 10.1002/macp.200700135] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Mezo G, Czajlik A, Manea M, Jakab A, Farkas V, Majer Z, Vass E, Bodor A, Kapuvári B, Boldizsár M, Vincze B, Csuka O, Kovács M, Przybylski M, Perczel A, Hudecz F. Structure, enzymatic stability and antitumor activity of sea lamprey GnRH-III and its dimer derivatives. Peptides 2007; 28:806-20. [PMID: 17254668 DOI: 10.1016/j.peptides.2006.12.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2006] [Revised: 12/19/2006] [Accepted: 12/20/2006] [Indexed: 11/24/2022]
Abstract
Direct antitumor activity of sea lamprey (Petromyzon marinus) gonadotropin-releasing hormone III (Glp-His-Trp-Ser-His-Asp-Trp-Lys-Pro-Gly-NH(2); lGnRH-III) was described on several tumor cells. To improve the selectivity of antitumor effects without increasing the hormone releasing activity and to enhance the enzymatic stability, lGnRH-III dimers were prepared via disulfide bond formation. Our results demonstrate that the lGnRH-III dimer derivatives exhibited higher antiproliferative effect and enzymatic stability in comparison with the native lGnRH-III, while lower LH-releasing potency was determined. In order to find a correlation between the biological and structural features of these compounds, the conformation of lGnRH-III and its dimer derivatives was determined by ECD, VCD, FT-IR and (1)H NMR.
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Mehdi H, Bodor A, Lantos D, Horváth IT, De Vos DE, Binnemans K. Imidazolium Ionic Liquids as Solvents for Cerium(IV)-Mediated Oxidation Reactions. J Org Chem 2006; 72:517-24. [PMID: 17221969 DOI: 10.1021/jo061909o] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Use of imidazolium ionic liquids as solvents for organic transformations with tetravalent cerium salts as oxidizing agents was evaluated. Good solubility was found for ammonium hexanitratocerate(IV) (ceric ammonium nitrate, CAN) and cerium(IV) triflate in 1-alkyl-3-methylimidazolium triflate ionic liquids. Oxidation of benzyl alcohol to benzaldehyde in 1-ethyl-3-methylimidazolium triflate was studied by in-situ FTIR spectroscopy and 13C NMR spectroscopy on carbon-13-labeled benzyl alcohol. Careful control of the reaction conditions is necessary because ammonium hexanitratocerate(IV) dissolved in an ionic liquid can transform benzyl alcohol not only into benzaldehyde but also into benzyl nitrate or benzoic acid. The selectivity of the reaction of cerium(IV) triflate with benzyl alcohol in dry ionic liquids depends on the degree of hydration of cerium(IV) triflate: anhydrous cerium(IV) triflate transforms benzyl alcohol into dibenzyl ether, whereas hydrated cerium(IV) triflate affords benzaldehyde as the main reaction product. Reactions of ammonium hexanitratocerate(IV) with organic substrates other than benzyl alcohol have been explored. 1,4-Hydroquinone is quantitatively transformed into 1,4-quinone. Anisole and naphthalene are nitrated. For the cerium-mediated oxidation reactions in ionic liquids, high reaction temperatures are an advantage because under these conditions smaller amounts of byproducts are formed.
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Szabó D, Mohl J, Bálint AM, Bodor A, Rábai J. Novel generation ponytails in fluorous chemistry: Syntheses of primary, secondary, and tertiary (nonafluoro-tert-butyloxy)ethyl amines. J Fluor Chem 2006. [DOI: 10.1016/j.jfluchem.2006.06.020] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Hódi Z, Németh AL, Radnai L, Hetényi C, Schlett K, Bodor A, Perczel A, Nyitray L. Alternatively Spliced Exon B of Myosin Va Is Essential for Binding the Tail-Associated Light Chain Shared by Dynein. Biochemistry 2006; 45:12582-95. [PMID: 17029413 DOI: 10.1021/bi060991e] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A 10 kDa dynein light chain (DLC), previously identified as a tail light chain of myosin Va, may function as a cargo-binding and/or regulatory subunit of both myosin and dynein. Here, we identify and characterize the binding site of DLC on myosin Va. Fragments of the human myosin Va tail and the DLC2 isoform were expressed, and their complex formation was analyzed by pull-down assays, gel filtration, and spectroscopic methods. DLC2 was found to bind as a homodimer to a approximately 15 residue segment (Ile1280-Ile1294) localized between the medial and distal coiled-coil domains of the tail. The binding region contains the three residues coded by the alternatively spliced exon B (Asp1284-Lys1286). Removal of exon B eliminates DLC2 binding. Co-localization experiments in a transfected mammalian cell line confirm our finding that exon B is essential for DLC2 binding. Using circular dichroism, we demonstrate that binding of DLC2 to a approximately 85 residue disordered domain (Pro1235-Arg1320) induces some helical structure and stabilizes both flanking coiled-coil domains (melting temperature increases by approximately 7 degrees C). This result shows that DLC2 promotes the assembly of the coiled-coil domains of myosin Va. Nuclear magnetic resonance spectroscopy and docking simulations show that a 15 residue peptide (Ile1280-Ile1294) binds to the surface grooves on DLC2 similarly to other known binding partners of DLCs. When our data are taken together, they suggest that exon B and its associated DLC2 have a significant effect on the structure of parts of the coiled-coil tail domains and such a way could influence the regulation and cargo-binding function of myosin Va.
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Orosz A, Szabo A, Szeman G, Janaky T, Somlai C, Penke B, Bodor A, Perczel A. Novel nontoxic heat shock protein 90 inhibitors having selective antiproliferative effect. Int J Biochem Cell Biol 2006; 38:1352-62. [PMID: 16540363 DOI: 10.1016/j.biocel.2006.01.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2005] [Revised: 01/20/2006] [Accepted: 01/27/2006] [Indexed: 11/23/2022]
Abstract
Almost all heat shock protein 90 inhibitors reported so far, which are natural product derivatives, have problems mainly with toxic side effects, and with bioavailability and solubility. In our earlier studies, we compared the steric conformational structures of substance P[6-11] with our substance P antagonists in silico, and used the diverse biological effects of these compounds as tools in our modeling and design studies for discovering antiproliferative drugs. Here, we present a new synthesized short peptide-derivative compound family that inhibits only the function of the tumor cell's heat shock protein 90 and selectively kills in vitro more cancer cells than normal cells. During the lead generation, we observed that the difference between the most effective inhibitors was only one residue or group that caused diverse effects in vitro on the studied cell lines. According to our in vivo experiments on nude mice bearing lung cancer xenografts, the inhibitors restrained tumor growth, but not caused overt toxicity. We undertook NMR spectroscopy studies to analyze the 3D molecular structural differences of our inhibitors that control their binding to the target molecule. In conclusion, we demonstrated the efficacy of new selective and small molecule anticancerogen heat shock protein 90 inhibitors with peptide nature, without in vivo toxicity on nude mouse xenograft model. Our results also shed light on the mechanism of anticancerogen action of some substance P antagonists and their derivatives.
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Pusztai Z, Vlád G, Bodor A, Horváth IT, Laas HJ, Halpaap R, Richter FU. In Situ NMR Spectroscopic Observation of a Catalytic Intermediate in Phosphine-Catalyzed Cyclo-Oligomerization of Isocyanates. Angew Chem Int Ed Engl 2006. [DOI: 10.1002/ange.200502415] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Pusztai Z, Vlád G, Bodor A, Horváth IT, Laas HJ, Halpaap R, Richter FU. In Situ NMR Spectroscopic Observation of a Catalytic Intermediate in Phosphine-Catalyzed Cyclo-Oligomerization of Isocyanates. Angew Chem Int Ed Engl 2006; 45:107-10. [PMID: 16304659 DOI: 10.1002/anie.200502415] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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