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61.
Rodina EV Vorobyeva NN Kurilova SA Belenikin MS Fedorova NV Nazarova TI 《Biochemistry. Biokhimii?a》2007,72(1):93-99
The interaction of Escherichia coli inorganic pyrophosphatase (E-PPase) with effector ATP has been studied. The E-PPase has been chemically modified with the
dialdehyde derivative of ATP. It has been established that in the experiment only one molecule of effector ATP is bound to
each subunit of the hexameric enzyme. Tryptic digestion of the adenylated protein followed by isolation of a modified peptide
by HPLC and its mass-spectrometric identification has showed that it is an amino group of Lys146 that undergoes modification.
Molecular docking of ATP to E-PPase indicates that the binding site for effector ATP is located in a cluster of positively
charged amino acid residues proposed earlier on the basis of site-directed mutagenesis to participate in binding of effector
pyrophosphate. Molecular docking also reveals several other amino acid residues probably involved in the interaction with
effectors.
Published in Russian in Biokhimiya, 2007, Vol. 72, No. 1, pp. 110–117. 相似文献
62.
Rodina EV Vorobyeva NN Kurilova SA Sitnik TS Nazarova TI 《Biochemistry. Biokhimii?a》2007,72(1):100-108
It has been shown that PPi, methylenediphosphonate, and ATP act as effectors of Escherichia coli inorganic pyrophosphatase (E-PPase), and that they compete for binding at the allosteric regulatory site. On the basis of
chemical modification and computer modeling of a structure of the enzyme-ATP complex, a number of amino acid residues presumably
involved in binding effectors has been revealed. Mutant variants Lys112Gln, Lys112Gln/Lys148Gln, and Lys112Gln/Lys115Ala of
E-PPase have been obtained, as well as a modified variant of wild type E-PPase (Adwt PPase) with a derivative of ATP chemically attached to the amino group of Lys146. Kinetic properties of these variants
have been investigated and compared to the earlier described variants Lys115Ala, Arg43Gln, and Lys148Gln. Analysis of the
data confirms the proposed location of an effector binding site in a cluster of positively charged amino acid residues including
the side chains of Arg43, Lys146 (subunit A), Lys112, and Lys115 (subunit B). Lys112 is supposed to play a key role in forming
contacts with the phosphate groups of the three studied effectors.
Published in Russian in Biokhimiya, 2007, Vol. 72, No. 1, pp. 118–127. 相似文献
63.
64.
Glutathione (GSH) content as well as GSH-peroxidase and GSH-reductase activity in isolated rat thymocytes X-irradiated in a dose of 4.5 Gy or treated with 0.1 mM H2O2 were studied in a period preceding the appearance of apoptosis morphological symptoms. The early adaptive response of thymocytes to radiation - increase of both GSH content and glutathione peroxidase and glutathione reductase activity was revealed. On the contrary the rapid fall of GSH level in H2O2-treated thymocytes was observed simultaneousely with glutathione reductase inhibition and enhanced GSH consumption by glutathione peroxidase, this disbalance of GSH-dependent antioxidant system probably facilitates mitochondrial way of apoptosis. 相似文献
65.
66.
Eric AF Sim?es Xavier Carbonell-Estrany John R Fullarton Johannes G Liese Jose Figueras-Aloy Gunther Doering Juana Guzman European RSV Risk Factor Study Group 《Respiratory research》2008,9(1):78
Background
The aim of this study, conducted in Europe, was to develop a validated risk factor based model to predict RSV-related hospitalisation in premature infants born 33–35 weeks'' gestational age (GA).Methods
The predictive model was developed using risk factors captured in the Spanish FLIP dataset, a case-control study of 183 premature infants born between 33–35 weeks'' GA who were hospitalised with RSV, and 371 age-matched controls. The model was validated internally by 100-fold bootstrapping. Discriminant function analysis was used to analyse combinations of risk factors to predict RSV hospitalisation. Successive models were chosen that had the highest probability for discriminating between hospitalised and non-hospitalised infants. Receiver operating characteristic (ROC) curves were plotted.Results
An initial 15 variable model was produced with a discriminant function of 72% and an area under the ROC curve of 0.795. A step-wise reduction exercise, alongside recalculations of some variables, produced a final model consisting of 7 variables: birth ± 10 weeks of start of season, birth weight, breast feeding for ≤ 2 months, siblings ≥ 2 years, family members with atopy, family members with wheeze, and gender. The discrimination of this model was 71% and the area under the ROC curve was 0.791. At the 0.75 sensitivity intercept, the false positive fraction was 0.33. The 100-fold bootstrapping resulted in a mean discriminant function of 72% (standard deviation: 2.18) and a median area under the ROC curve of 0.785 (range: 0.768–0.790), indicating a good internal validation. The calculated NNT for intervention to treat all at risk patients with a 75% level of protection was 11.7 (95% confidence interval: 9.5–13.6).Conclusion
A robust model based on seven risk factors was developed, which is able to predict which premature infants born between 33–35 weeks'' GA are at highest risk of hospitalisation from RSV. The model could be used to optimise prophylaxis with palivizumab across Europe. 相似文献67.
Karl Y. Biel Irina R. Fomina Galina N. Nazarova Vladislav G. Soukhovolsky Rem G. Khlebopros John N. Nishio 《Protoplasma》2010,245(1-4):49-73
The localization of the key photoreductive and oxidative processes and some stress-protective reactions within leaves of mesophytic C3 plants were investigated. The role of light in determining the profile of Rubisco, glutamate oxaloacetate transaminase, catalase, fumarase, and cytochrome-c-oxidase across spinach leaves was examined by exposing leaves to illumination on either the adaxial or abaxial leaf surfaces. Oxygen evolution in fresh paradermal leaf sections and CO2 gas exchange in whole leaves under adaxial or abaxial illumination was also examined. The results showed that the palisade mesophyll is responsible for the midday depression of photosynthesis in spinach leaves. The photosynthetic apparatus was more sensitive to the light environment than the respiratory apparatus. Additionally, examination of the paradermal leaf sections by optical microscopy allowed us to describe two new types of parenchyma in spinach—pirum mesophyll and pillow spongy mesophyll. A hypothesis that oxaloacetate may protect the upper leaf tissue from the destructive influence of active oxygen is presented. The application of mathematical modeling shows that the pattern of enzymatic distribution across leaves abides by the principle of maximal ecological utility. Light regulation of carbon metabolism across leaves is discussed. 相似文献
68.
It is shown that BR and intermediate products of its phototransformation P600, P550 and P415 (the maximum at -196 degrees C at 419 nm) are not paramagnetic. Illumination of samples containing P415 (P419) at -- 196 degrees C with light in the region of 360-480 nm results in the formation of paramagnetic centres with a sunglet spectrum deltaH=18 Oe and g=2.002 (R1). In parallel formation of a new photoproduct P421 in the absorption spectrum is observed. During subsequent heating at -140 degrees C formation of an asymmetric signal with deltaH=45 Oe and g=2.006 and g=2.03 was observed. In the absorption spectra a dark transition. P421-P565 was observed under the same conditions. P565 differs from initial BR P570 as to its photochemical properties. R1 is identified as retinal radical, R2 as a peroxide radical of the BR-complex lipids. Paramagnetic, spectral, and photochemical properties of some products of BR transformation are compared. A scheme of oxidative-phosphorylation processes with participation of Mn ions in BR phototransformation. 相似文献
69.
Petrova OP Nazarova LA 《Rossi?skii fiziologicheski? zhurnal imeni I.M. Sechenova / Rossi?skaia akademiia nauk》2005,91(4):431-436
In 9 experimental rabbit fetuses (with reduced uterine-placental blood frow), noradrenaline administration led to an obvious thermogenic response and heart rate increase, but not in intact rabbits. Obviously the noradrenaline dosage corresponds to the range of adaptive capacities of the functional systems in intact fetuses and so does not induce any shifts of the homeostasis parameters in them. The experimental fetuses prove to be more vulnerable to stresses, and homeostasis parameter shifts in them are statistically significant. 相似文献
70.
Touré A Clemente EJ Ellis P Mahadevaiah SK Ojarikre OA Ball PA Reynard L Loveland KL Burgoyne PS Affara NA 《Genome biology》2005,6(12):R102-15