Báo cáo khóa học: Insight into the activation mechanism of Bordetella pertussis adenylate cyclase by calmodulin using ﬂuorescence spectroscopy pptx

... transition in AC (Eur. J. Biochem. 271) 833 Insight into the activation mechanism of Bordetella pertussis adenylate cyclase by calmodulin using ﬂuorescence spectroscopy Jacques Gallay1, Michel Vincent1, ... direct exploitation of the structural results of the former to explain the mechanism of CaM activation of the latter. Crystallizationand resolution of the 3D structures of AC and AC–CaM,which ... France The interaction of the adenylate cyclase catalytic domain(AC) of the Bordetella pertussis major exotoxin with itsactivator calmodulin (CaM) was studied by time-resolved ﬂuorescence spectroscopy...

Báo cáo khoa học: Insight into the phosphodiesterase mechanism from combined QM ⁄ MM free energy simulations pot

... to model the hydrolysis of cAMP by the enzyme PDE4B, which provides furtherinsights on the general features of phosphate hydrolysis. The PDE superfamily of enzymes can be classiﬁed into 11 members ... Although the structure of a small frag-ment of PDE4D was reported in 1996 [5,13], keyinsights into the understanding of the catalytic activesite of PDEs were obtained following the determination of ... with the side chain of Glu304 and the backbone of Thr345. Interestingly, the side chain of Thr345,together with the backbone of His274, forms a stableH-bond with the two hydrogen atoms of H2O24...

Tài liệu Báo cáo khoa học: nsights into the reaction mechanism of glycosyl hydrolase family 49 Site-directed mutagenesis and substrate preference of isopullulanase doc

... mechanism of h ydrolysis of IPU and o therGH family 49 dextranases, the a nomer conﬁguration of the hydrolysate of IPU was determined. A polarimetric assaywas carried out using panose as the substrate. ... activating the nucleophilic water m olecule) in the ﬁrst step of the reaction.A carbonium ion intermediate subsequently forms, and isfurther attacked by the water molecule. The study of site-directed ... ID, 1OGO) [17]. The identity between the primary structures of Dex49A a ndIPU is 38%, and a t hree-dimensional structure of IPU wasmodelled based on the structure of Dex49A using the Swiss-Model...

Báo cáo khoa học: Insights into the activation of brain serine racemase by the multi-PDZ domain glutamate receptor interacting protein, divalent cations and ATP ppt

... Activation of brain SR requires the presence of GAP2 together withPDZ7. Interestingly, in the absence of additional ATP, the activation induced by the presence of the PDZ4-PDZ5-PDZ6-GAP2-PDZ7-end of ... carbonylgroups. Both the geometry and the distances perfectlyagree with the coordination of these metals [23]. The Fig. 4. Binding of ATP to SR changes the Vmax of the racemization reaction but not the oligomeric ... in the reaction mixture.Characterization of the activation of brain SR by GRIP(468–1112)We next analysed whether larger ratios of PDZ6domain:SR might be able to increase the synthesis of d-serine....

Tài liệu Báo cáo Y học: Insights into the reaction mechanism of Escherichia coli agmatinase by site-directed mutagenesis and molecular modelling ppt

... coliagmatinase, of the loop indicated by the letter a.Fig. 5. Scheme of the binuclear manganese cluster and the localization of the side-chains of Asp153 and Asn153 in the modelled structures of wild-type ... with the sameregion of the arginases (Fig. 4). Since the arginase loopcontains residues that interacts with the a-carboxylategroup of the substrate arginine [13], and this is the part of the ... and the carboxamideoxygen of Asn153 are positioned in such a way as to allowmetal coordination interaction with one of the manganeseions. This, together with the fact that the positions of otherFig....

Báo cáo khoa học: Bacitracin inhibits the reductive activity of protein disulﬁde isomerase by disulﬁde bond formation with free cysteines in the substrate-binding domain pptx

... 10 mm). The structural identity of the isolated analogs was con-ﬁrmed by MALDI-TOF ⁄ TOF MS, with a 4800 MALDI-TOF ⁄ TOF Analyzer (AB SCIEX, Framingham, MA,USA). MALDI-TOF and TOF ⁄ TOF MS spectra ... involved in the crosslink by the sin-gle-letter code. The PDI peptide side of the disulﬁde bond is named R1, and the bacitracin side R2. (C) MALDI-TOF MS spectrum of pep-tides generated by tryptic ... ring of bacitracin A (937.33).Negative ion mode CID-TOF ⁄ TOF MS analysis of the same precursor yielded the corresponding signaturepeaks (m ⁄ z 1404.88, 1438.82 and 1470.80) of the otherpart of...

Báo cáo khoa học: Deﬁning the QP-site of Escherichia coli fumarate reductase by site-directed mutagenesis, ﬂuorescence quench titrations and EPR spectroscopy doc

... effects on the EPR properties of FrdABCD. In the case of the FrdB-T205H mutant, the [3Fe-4S] cluster line-shape isnarrower than that of the wild-type (note the position of the trough in the spectrum ... Looking along the axis deﬁ-ned by the two keto-oxygens of the prox-imal menaquinone (MQ) naphthoquinonebicycle. (B) Looking along the axis of the MQ towards the isoprenoid chain. (C) The same perspective ... QPsite (the proximal Q-site), is located in the interface region between the FrdCD subunits and the [3Fe-4S] cluster coordinating region of FrdB on the cytoplasmic side of the membrane. The other...

Tài liệu Báo cáo khoa học: Insights into the structure of plant a-type phospholipase D Susanne Stumpe, Stephan Konig and Renate Ulbrich-Hofmann ¨ ppt

... than the measurements of inactivation, show the sametrends with respect to the effects of NaCl, CaCl2andEDTA as the inactivation constants. As shown by SDS ⁄ PAGE (Fig. 5), the decrease in ﬂuorescence intensity ... [20,21].In the present study, the ﬁrst insights into the secon-dary and tertiary structure of PLD a2 from cabbageare given. The surface structure of the enzyme wasinvestigated by small-angle ... the typical range for aspherical particle. The bell-shaped distance distributionfunction illustrates the quality of the experimental data(Fig. 2B).Reconstruction of the overall shape of the...

Tài liệu Báo cáo khoa học: Insights into the interaction of human arginase II with substrate and manganese ions by site-directed mutagenesis and kinetic studies Alteration of substrate speciﬁcity by replacement of Asn149 with Asp docx

... as a consequence of the mutagenic replacements.Effects of the His120Asn and His145Asnmutations on the affinity of metal bindingto arginase IITo further examine the effects of the His120fiAsnand ... ana-lysis of the effect was not performed, the inhibition by 20 mm agmatine was eliminated by saturation withl-arginine, indicating the competitive character of the inhibition produced by the substrate ... addition to removal of the more weakly bound Mn2+, the lower affinity for thatmore tightly bound to the protein may explain the absence of Mn2+from the EDTA-treated species of the His145Asn variant....

Báo cáo khoa học: Investigations into the ability of an oblique a-helical template to provide the basis for design of an antimicrobial anionic amphiphilic peptide pot

... which facili-tates their interaction with the anionic membranes of microbial cells, and they exert their antimicrobialaction by the use of nonreceptor-based mechanisms of Keywordsanionic; ... contribute to the susceptibility of E. coli model membranes to the action of AP1.An important determinant of the susceptibility of membranes to a-AMPs is the packing characteristics of the individual ... stablein the presence of AP1, further supporting the sugges-tion that this instability may contribute to the susceptibility of E. coli to the antimicrobial action of the peptide.Discussion The biological...

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