CCL

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1.

001-es BibID:BIBFORM031388
Első szerző:Böcskei Z.
Cím:Crystallization and preliminary X-ray analysis of porcine muscle prolyl oligopeptidase / Z. Böcskei, M. Fuxreiter, G. Náray-Szabó, E. Szabó, L. Polgar
Dátum:1998
Megjegyzések:Prolyl oligopeptidase from pig muscle has been crystallized in complex with an inhibitor, using PEG 8000 and calcium acetate as precipitants. The crystals are orthorombic and the space group is P212121 with cell dimensions a = 111.8, b = 101.8, c = 72.4 Å. The asymmetric unit contains a single chain of prolyl oligopeptidase, corresponding to a specific volume of 2.55 Å3 Da-1 and a solvent content of 52%. The observed diffraction pattern extends to 2.3 Å resolution and the native crystals are well suited for structural analysis by X-ray diffraction methods.
Tárgyszavak:Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
egyetemen (Magyarországon) készült közlemény
Megjelenés:Acta crystallographica. Section D, Biological crystallography. - 54 : S2 (1998), p. 1414-1415. -
További szerzők:Náray-Szabó Gábor Szabó E. Polgár László Fuxreiter Mónika (1969-) (kutató vegyész)
Internet cím:DOI
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2.

001-es BibID:BIBFORM031413
035-os BibID:PMID:9188736 WOS:A1997XD03700007
Első szerző:Fuxreiter Mónika (kutató vegyész)
Cím:Role of electrostatics at the catalytic metal binding site in xylose isomerase action : Ca(2+)-inhibition and metal competence in the double mutant D254E/D256E / Fuxreiter M., Bocskei Z., Szeibert A., Szabo E., Dallmann G., Naray-Szabo G., Asboth B.
Dátum:1997
ISSN:0887-3585
Megjegyzések:The catalytic metal binding site of xylose isomerase from Arthrobacter B3728 was modified by protein engineering to diminish the inhibitory effect of Ca2+ and to study the competence of metals on catalysis. To exclude Ca2+ from Site 2 a double mutant D254E/D256E was designed with reduced space available for binding. In order to elucidate structural consequences of the mutation the binary complex of the mutant with Mg2+ as well as ternary complexes with bivalent metal ions and the open-chain inhibitor xylitol were crystallized for x-ray studies. We determined the crystal structures of the ternary complexes containing Mg2+, Mn2+, and Ca2+ at 2.2 to 2.5 Angstrom resolutions, and refined them to R factors of 16.3, 16.6, and 19.1, respectively. We found that all metals are liganded by both engineered glutamates as well as by atoms O1 and O2 of the inhibitor. The similarity of the coordination of Ca2+ to that of the cofactors as well as results with Be2+ weaken the assumption that geometry differences should account for the catalytic noncompetence of this ion. Kinetic results of the D254E/D256E mutant enzyme showed that the significant decrease in Ca2+ inhibition was accompanied by a similar reduction in the enzymatic activity. Qualitative argumentation, based on the protein electrostatic potential, indicates that the proximity of the negative side chains to the substrate significantly reduces the electrostatic stabilization of the transition state. Furthermore, due to the smaller size of the catalytic metal site, no water molecule, coordinating the metal, could be observed in ternary complexes of the double mutant. Consequently, the proton shuttle step in the overall mechanism should differ from that in the wild type. These effects can account for the observed decrease in catalytic efficiency of the D254E/D256E mutant enzyme.
Tárgyszavak:Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
egyetemen (Magyarországon) készült közlemény
Megjelenés:Proteins. - 28 : 2 (1997), p. 183-193. -
További szerzők:Szeibert A. Szabó E. Dallmann, G. Náray-Szabó Gábor Asboth, B. Böcskei Z.
Internet cím:DOI
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3.

001-es BibID:BIBFORM031387
035-os BibID:WOS:A1995TL57300009
Első szerző:Fuxreiter Mónika (kutató vegyész)
Cím:Molecular modelling of xylose isomerase catalysis : the role of electrostatics and charge transfer to metals / Mónika Fuxreiter, Ödön Farkas, Gábor Náray-Szabó
Dátum:1995
ISSN:0269-2139
Megjegyzések:The two main steps of the mechanism of xylose-xylulose conversion catalysed by D-xylose isomerase, the ring opening of xylose and the isomerization of the opened product by hydride transfer, were investigated by molecular mechanical and molecular orbital techniques. The activation energies calculated for these reactions clearly showed that hydrogen transfer is the rate-determining step of the enzymatic isomerization and that Mg2+ ions activate whereas Zn2+ ions inhibit the reaction, in agreement with the experiments. The remarkable differences between the net charges of these ions found by molecular orbital calculations and the inspection of the protein electrostatic potential around the reaction intermediates indicate that the main role of bivalent metal ions should be the electrostatic stabilization of the substrate transition states. In order to propose a more detailed mechanism, an attempt was made to clarify the effects of nearby residues (e.g. His54, Asp57, Lysl83, Asp257) in the reaction. Different isomerization mechanisms, such as through an enediol intermediate, were examined and could be excluded, in addition to the charge-relay mechanism during the ring opening.
Tárgyszavak:Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
egyetemen (Magyarországon) készült közlemény
Megjelenés:Protein engineering. - 8 : 9 (1995), p. 925-933. -
További szerzők:Farkas Ödön Náray-Szabó Gábor
Internet cím:DOI
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4.

001-es BibID:BIBFORM031415
035-os BibID:WOS:000078985400009 PMID:10499105
Első szerző:Martel, Paulo J.
Cím:Comparative redox and Pka calculations on cytochrome c3 from several desulfovibrio species using continuum electrostatic methods / Paulo J. Martel, Cláudio M. Soares, António M. Baptista, Monika Fuxreiter, Gábor Náray-Szabó, Ricardo O. Louro, Maria A. Carrondo
Dátum:1999
Megjegyzések:A comparative study of the pH-dependent redox mechanisms of several members of the cytochrome c(3) family has been carried out. In a previous work, the molecular determinants of this dependency (the so-called redox-Bohr effect) were investigated for one species using continuum electrostatic methods to find groups with a titrating range and strength of interaction compatible with a mediating role in the redox-Bohr effect. Here we clarify these aspects in the light of new and improved pK(a) calculations, our findings supporting the hypothesis of propionate D from heme I being the main effector in the pH-dependent modulation of the cytochrome c(3) redox potentials in all the a molecules studied here. However, the weaker (but significant) role of other titrating groups cannot be excluded, their importance and identity changing with the particular molecule under study. We also calculate the relative redox potentials of the four heme centers among the selected members of the c(3) family, using a continuum electrostatic method that takes into account both solvation and interaction effects. Comparison of the calculated values with available data for the microscopic redox potentials was undertaken, the quality of the agreement being dependent upon the choice of the dielectric constant for the protein interior. We find that high dielectric constants give best correlations, while low values result in better magnitudes for the calculated potentials. The possibility that the crystallographic calcium ion in c(3) from Desulfovibrio gigas may be present in the solution structure was tested, and found to be likely.
Tárgyszavak:Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
külföldön készült közlemény
Megjelenés:Journal of biological inorganic chemistry. - 4 : 1 (1999), p. 73-86. -
További szerzők:Soares, Cláudio M. Baptista, António M. Fuxreiter Mónika (1969-) (kutató vegyész) Náray-Szabó Gábor Louro, Ricardo O. Carrondo, Maria A.
Internet cím:DOI
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5.

001-es BibID:BIBFORM054887
Első szerző:Náray-Szabó Gábor
Cím:Electrostatic basis of enzyme catalysis / G. Náray-Szabó, M. Fuxreiter, A. Warshel
Dátum:1997
ISBN:0-7923-4512-6
Tárgyszavak:Orvostudományok Elméleti orvostudományok könyvfejezet
Megjelenés:Computational approaches to biochemical reactivity / ed. by Gábor Náray-Szabó, Arieh Warshel. - p. 237-293. -
További szerzők:Fuxreiter Mónika (1969-) (kutató vegyész) Warshel, Arieh
Internet cím:Intézményi repozitóriumban (DEA) tárolt változat
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