modulation of catalytic activity and binding properties of proteins by lipids

... identified by NMR-monitored titrations of Bacillus circulans xylanase [13] and X-ray analysis of crystals of catalytically incompetent mutants of the xylanases of Bacillus subtilis (XBS) and Aspergillus ... Obviously, substrate binding is closely linked to activity Therefore, the binding of the different XBS and XAN mutants towards water-unextractable AX and OSX was assessed by constructing binding curves, ... the ratio of activity on Xylazyme AX and activity on X6 Screening ratios are expressed relative to the ratio of the wild-type enzyme (100%) and were calculated based on two independent activity...

Ngày tải lên: 14/02/2014, 19:20

... amounts of the 38-kDa mature form (s) and the wild-type enzyme (d) on the rate of ligation Catalytic and substoichiometric amounts (molar ratio of 0.01 and 0.1, respectively) of these proteins ... pH 7.0 and °C for h, followed by SDS ⁄ PAGE The rate of ligation was estimated from percentage intensity of the band of the 57-kDa protein in a total of intensities of the 57-kDa, 38-kDa and 19-kDa ... form and the isolated 19-kDa propeptide are mixed; lanes d, the purified proenzyme (a mixture of the nicked and intact forms of the precursor) Proteins were detected by silver staining The band of...

Ngày tải lên: 19/02/2014, 07:20

... mutation of Thr15 to Ala in the vicinity of the hydrophobic core induces a tighter binding of the cofactor in C freundii TPL, thereby reducing the decomposition rate of the cofactor by a Pictet–Spengler ... the catalytic lysine residue 6190 70 Temperature (ºC) Relative activity (%) Specific activity (units·mg–1) Temperature (ºC) 10 11 Fig Effect of temperature and pH on stability and catalytic activity ... mutations from both the stability and activity mutants, and demonstrated a significant improvement in both stability and catalytic activity (Fig 1) As such, the activity and stability mutation combinations...

Ngày tải lên: 07/03/2014, 00:20

... adaptability of HSA involves more than the immediate vicinity of the binding site(s), affecting both the structure and the ligand -binding properties of the whole HSA molecule, which displays ligand-dependent ... Allosteric properties of truncated albumin G Fanali et al References Optical binding studies Fe(III)heme binding to HSA and tHSA, in the absence and presence of 1.0 · 10)4 m ibuprofen and 1.0 · ... HSA, tHSA contains the primary binding sites for heme and warfarin, and the secondary ibuprofen -binding site (Fig 1) Results and Discussion Dynamics and hydration of tHSA Fig Heme (Protein Data...

Ngày tải lên: 23/03/2014, 04:21

... thermal inactivation Catalytic properties and specificity of the P/CAF enzymes C D The kinetic parameters of the wild-type and mutant P ⁄ CAF enzymes for acetylation of the histone H3 and H4 peptides ... which half of the initial activity is lost in The activity half-life t1 ⁄ 2, 48 °C of the proteins was determined at 48 °C by incubating the proteins for 0–1800 at 48 °C, followed by incubation ... potential binding interactions to partner proteins by stabilizing residues The mutations that are most effective in raising the thermostability of the catalytic domain of P ⁄ CAF (V582A, D601G and...

Ngày tải lên: 23/03/2014, 06:20

... fulfillment of requirements for a doctoral degree of engineering Catalytic activity and reaction mechanism of Au/TiO2 for the reduction of NOx by propene By Nguyen Quang Long 06D51501 (Supervised by Professor ... understand the catalytic activity of Au-based catalyst This study, in general, aims to investigate the catalytic activity and the reaction mechanism of Au-based catalysts for the reduction of NOx by ... objectives of the present research are as follows: To prepare and test the catalytic activity of nano-sized Au/TiO2 for SCR of NOx by propene To investigate the effect of mechanical additions of CeO2 and...

Ngày tải lên: 13/11/2014, 05:57

... W366 and Y394 residues of the D2 domain may play a role similar to that of binding sites I and II of GA-1 Mutations of W366 and Y394 in D123 decreased the starch -binding capacity by three- and ... with CD, and that this interaction enhances the catalytic activity of the enzyme Our results show that the interaction between SBDs and CD, as well as the full starch -binding capacity of the D2 ... highlighted by black bars (b strand), grey bars (helix) and white bars (coil) D2 and D3 domains are indicated by arrows Stars indicate the positions of W366 and Y394 D(316–344) and D(495–535) regions...

Ngày tải lên: 22/03/2014, 21:20

... different marker proteins as standards followed by HpSSB A standard curve was plotted using the log molecular mass values of various standard proteins against the fraction numbers of the proteins at ... Investigation of the role of individual tryptophan residues in the binding of Escherichia coli single-stranded DNA binding protein to single-stranded polynucleotides A study by optical detection of magnetic ... Effect of HpSSB on ATPase activity of HpDnaB in the presence of ssDNA The release of radiolabeled Pi from (c-32P)ATP was monitored in the absence and presence of different concentrations of HpSSB...

Ngày tải lên: 30/03/2014, 02:20

... different changes of enzymatic properties in AMY1/Trp a drastic loss of activity towards starch and maltodextrin, and Ala and Asp both retained activity on starch but highly decreased activity for ... (2001) Modulation of 5390 H Mori et al (Eur J Biochem 269) 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 activity and substrate binding modes by single and double subsites +1/+2 and )5/)6 mutation of ... segments of ba loops and (i.e domain B) from AMY2 (in green) and TAA (in black) The superimpositioning was guided by the catalytic acids (D179AMY2, E204AMY2, and D289AMY2 and D206TAA, E230TAA, and...

Ngày tải lên: 31/03/2014, 08:20

... determinant of Km (binding afnity), and is not affected by the mutation Figure shows the environment of residue 74, including the proximal residues of the TIM active site The isomerization of dihydroxyacetone ... observed effects of the Y74W mutation in PfTIM on the stability of the dimeric structure and catalytic activity Examination of the available TIM sequences provides examples of where this mutation ... and TIM were used for the rst round of mutagenesis in this case The presence of mutations was conrmed by sequencing (Microsynth, Balgach, Switzerland), and the mutants were found to be free of...

Ngày tải lên: 18/02/2014, 11:20

... a total volume of 20 lL Reactions were stopped by the addition of 100 lL of 2· Kirby buffer [25] and 80 lL of H2O, and rRNA was obtained by precipitation after two phenol– chloroform extractions ... affecting the activity of ricin A chain (Eur J Biochem 271) 159 Fig Assessment of the N-glycosidase activity and cytotoxicity of RTA N78S and ricin N78S (A) N-glycosidase activity of RTA N78S Isolated ... substrate binding or the catalytic reaction itself Both roles are Fig Assessment of the N-glycosidase activity and cytotoxicity of RTA N122A and ricin N122A (A) N-glycosidase activity of RTA N122A...

Ngày tải lên: 19/02/2014, 12:20

... site and makes six hydrogen bonds to Asp30 and Asp29 The importance of this residue and the strength of its binding to protease are supported also by the fact that it has the lowest B-factors of ... factor is a result of probable disorder of W401 caused by two orientations of inhibitor and asymmetrical binding of water with respect to the noncrystallographic C2 axis The positions of two inhibitor ... case of Ônarrow tunnelÕ, the diameter of the effective view through the solvent channel is 8.7 A (determined by distance of projections of two opposite Cc atoms of Phe53 and Phe153) In the case of...

Ngày tải lên: 19/02/2014, 16:20

... transport of lipophilic compounds and drugs and of medium and long chain fatty acids; among them, myristic acid is a stereotypic ligand to investigate fatty acid binding and transport properties of ... core of the model was based on the competition between Mn(III)heme and myristate for binding to FA1 (defined by the parameters KH and KM) and on the allosteric modulation of FA1 properties by myristate ... required for the synthesis of membrane lipids, hormones and second messengers, and serve as an important source of metabolic energy Although the binding of fatty acids to human and bovine serum albumin...

Ngày tải lên: 20/02/2014, 02:22

... switch and alters the expression of the two nuclear genome coded isoforms of CytOX V [10,32] The regulation of genes CytOX5a and CytOX5b, coding for the two isofoms Va and Vb, parallels that of genes ... Effect of hypoxia on CytOX activity, mitochondrial heme aa3 content and TN (s)1) in macrophages and PC12 cells CytOX activity in submitochondrial particles (SMP) from standard (141 Torr O2) and ... stages of adaptive response to hypoxia Based on the results of our study and those of Schumacker, it is reasonable to conclude that the effects of hypoxia on CytOX gene expression and its activity...

Ngày tải lên: 20/02/2014, 23:20

... interpretation and modelling of Cu(II) and Ni(II) transport by albumins On the other hand, the direct thermodynamic and kinetic characterization of Ni(II) binding at site I in HSA and BSA was obtained ... Characterization of the copper (II) and nickel (II)-transport site of human serum albumin Studies of copper (II) and nickel (II) binding to peptide 124 of human serum albumin by 13C and 1H NMR spectroscopy ... thereby providing another level of competition for metal ion binding Kinetics of Ni(II) binding and Cu(II)/Ni(II) exchange The data presented in Table demonstrate that the process of Ni(II) binding...

Ngày tải lên: 22/02/2014, 04:20

... domains of the protein We compared the Ca2+ -binding and Mg2+ -binding properties of Calnuc, and elucidated the physiological relevance of its interaction with G -proteins, using a variety of spectroscopic ... the EF-hands (as shown by the disappearance of both the c-band and the J-band) Magnesium ions on the other hand, behave differently, and seem to have specific affinity for only one of the binding ... sites Mg2+ binding reduces the intensities of only the c-band, and does not cause any change to the J-band A comparison of the spectral band pattern properties of Stains-all upon binding to Calnuc...

Ngày tải lên: 07/03/2014, 00:20

... backbones of the A and C monomers show tighter associa- Stabilization of pyranose oxidase tion in L537G by 1.4 A, and only by 0.9 A in L537W E542K, compared to model 2IGO As a result of these ... head domain of up to 4.3 A, and of exposed parts of the Rossmann domain of up to 2.7 A, are observed For the rest of the homotetrameric assembly, only smaller backbone displacements of up to ... efciency of the lysis Cell debris was removed by centrifugation, and 10 lL of the supernatant were added to 80 lL of chromogenic assay mixture (0.035 mgặmL)1 of horseradish peroxidase and 0.7...

Ngày tải lên: 07/03/2014, 03:20

... the binding and relative orientation of the cofactor and the substrate in the active site of the enzyme [10] A structure of the catalytically active ternary complex among enzyme, substrate and ... Binding of oxidized FMN to the mutant proteins To characterize the serine mutant proteins in further detail, binding of the oxidized FMN cofactor to the isolated apoproteins was investigated by UV ... order to investigate the influence of the amino acid replacements on the catalytic activity of chorismate synthase, we measured the activity of the mutant proteins An activity assay under aerobic conditions...

Ngày tải lên: 07/03/2014, 05:20

... represent < 1% of the activity of the wild-type enzyme We then determined, by photoaffinity labeling, whether any of the mutations altered the apparent binding affinity of Abcb1a for ATP Purified and activated ... Trapping of nucleotide by Vi requires both hydrolysis of the bond between the b- and c-phosphates of ATP and release of Pi Vi can replace Pi once it is released, capturing ADP in the nucleotide -binding ... dependent on the presence of Vi and is strongly stimulated by verapamil and valinomycin (Fig 3) Despite the observed lack of ATPase activity of the nine mutants analyzed (as measured by Pi release), 8-azido-nucleotide...

Ngày tải lên: 07/03/2014, 06:20

... the spectroscopic and ligand -binding studies of chlorite dismutase suggest binding of chlorite to the five-co-ordinate high-spin ferric form of the enzyme as the first step of the catalytic mechanism ... nitric oxide and catalase in the activation of guanylate cyclase by sodium azide and hydroxylamine Modulation of enzyme responses by heme proteins and their nitrosyl derivatives J Biol Chem 254, ... H39G with imidazole as proximal ligand has shown that NO reduces the binding constant of the imidazole by several orders of a magnitude [21] Furthermore, binding of NO trans to the histidine has...

Ngày tải lên: 08/03/2014, 16:20