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1.
The role of DnaJ-like proteins in glucocorticoid receptor.hsp90 heterocomplex assembly by the reconstituted hsp90.p60.hsp70 foldosome complex 总被引:1,自引:0,他引:1
The glucocorticoid receptor (GR) is recovered from hormone-free cells in a heterocomplex with the molecular chaperone hsp90, which is required to produce the proper folding state for steroid binding. GR.hsp90 heterocomplexes are formed by a multiprotein system that appears to exist in all eukaryotic cells. Recently, we have reconstituted a receptor.hsp90 heterocomplex assembly system with purified rabbit hsp90 and hsp70 and bacterially expressed human p23 and p60. We have shown that hsp90, p60, and hsp70 form an hsp90.p60. hsp70 complex that converts the GR from a non-steroid binding to a steroid binding form (Dittmar, K. D., and Pratt, W. B. (1997) J. Biol. Chem. 272, 13047-13054). The resulting GR.hsp90 heterocomplex rapidly disassembles unless p23 is present to bind to the ATP-dependent conformation of hsp90 and stabilize its association with the receptor (Dittmar, K. D., Demady, D. R., Stancato, L. F., Krishna, P., and Pratt, W. B. (1997) J. Biol. Chem. 272, 21213-21220). In the current work, we show that the purified rabbit hsp70 utilized in prior studies is contaminated with a small amount of the rabbit DnaJ homolog hsp40. Elimination of the hsp40 from the purified GR.hsp90 assembly system reduces assembly activity, and the activity is restored by addition of the purified yeast DnaJ homolog YDJ-1. hsp40 is a component of the hsp90.p60.hsp70 foldosome complex isolated from reticulocyte lysate with antibody against p60. Under conditions that promote binding of p23 to hsp90 (elevated temperature, ATP, Nonidet P-40, molybdate), a five-membered (p23. hsp90.p60.hsp70.hsp40) complex of chaperone proteins is formed in reticulocyte lysate or from purified proteins. The hsp40-free, purified assembly system has a modest level of assembly activity that is maximally potentiated by YDJ-1 when it is present at about one-twentieth the concentration of hsp70. Although hsp40 is not in the final GR.hsp90 heterocomplex isolated from L cell cytosol, it is in the GR.hsp90 heterocomplex assembled in reticulocyte lysate. We conclude that hsp40 is a component of the multiprotein hsp90-based chaperone system where it potentiates GR.hsp90 heterocomplex assembly. 相似文献
2.
The effect of methanol, acetone, formalin and glucose on the nitrification process in the packed bed reactors has been investigated. For the utilized compounds the inhibition constant Ki was determined according to Dixon's method. The determined values were as follows: methanol Ki = 116.0 mg l?1; acetone Ki = 804.2 mg l?1; formalin Ki = 61.5 mg l?1. The value of Ki for glucose has not been determined because glucose in applied concentration up to 11,325 mg l?1 had no effect on the nitrification course. 相似文献
3.
The temperature programmed (palladium) hydride decomposition appeared very effective method for diagnosing the extent of alloying in Pd-Pt/SiO2 catalysts. Introduction of Pt to Pd catalysts moves the TPHD peak gradually towards lower temperatures and the shift in hydride decomposition peak is accompanied by a decrease in the amount of released hydrogen. The catalysts prepared the direct redox method showed much better alloy homogeneity than the samples prepared by coimpregnation. The results of probing with other techniques, i.e. catalytic probing with hydrodechlorination of CCl2F2 and XRD, were in line with TPHD data. The catalytic probing showed the presence of synergistic effect, a clear indication of Pd-Pt mixing. XRD data of post-reaction samples showed carbon incorporation into Pd-rich phase, whereas separate Pt-rich phase did not experience any bulk carbiding. 相似文献
4.
5.
Zbigniew W. Kowalski 《Journal of Materials Science》1985,20(5):1521-1555
It is the purpose of the paper to promote the ion beam sputtering technique and its biomedical applications among not only ion beam users but also other research workers, and especially, among biologists and medical doctors. The objectives of this article are threefold. Firstly, it supplies a conceptual background for discussing the main question of this work, i.e. biomedical applications of sputtering. Secondly, the title issue and some related problems, important in the biomedical use, are widely presented and discussed. Finally, clinical implication and potential applications are shown. 相似文献
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7.
Magdalena Ptak-Kaczor Mateusz Banach Katarzyna Stapor Piotr Fabian Leszek Konieczny Irena Roterman 《International journal of molecular sciences》2021,22(9)
Protein solubility is based on the compatibility of the specific protein surface with the polar aquatic environment. The exposure of polar residues to the protein surface promotes the protein’s solubility in the polar environment. The aquatic environment also influences the folding process by favoring the centralization of hydrophobic residues with the simultaneous exposure to polar residues. The degree of compatibility of the residue distribution, with the model of the concentration of hydrophobic residues in the center of the molecule, with the simultaneous exposure of polar residues is determined by the sequence of amino acids in the chain. The fuzzy oil drop model enables the quantification of the degree of compatibility of the hydrophobicity distribution observed in the protein to a form fully consistent with the Gaussian 3D function, which expresses an idealized distribution that meets the preferences of the polar water environment. The varied degrees of compatibility of the distribution observed with the idealized one allow the prediction of preferences to interactions with molecules of different polarity, including water molecules in particular. This paper analyzes a set of proteins with different levels of hydrophobicity distribution in the context of the solubility of a given protein and the possibility of complex formation. 相似文献
8.
Marta Krychowiak-Manicka Mirosawa Krauze-Baranowska Sylwia Godlewska Zbigniew Kaczyski Aleksandra Bielicka-Giedo Natalia Grzegorczyk Magdalena Narajczyk Joanna E. Frackowiak Aleksandra Krolicka 《International journal of molecular sciences》2021,22(9)
Carnivorous plants are exemplary natural sources of secondary metabolites with biological activity. However, the therapeutic antimicrobial potential of these compounds is limited due to intrinsic resistance of selected bacterial pathogens, among which Pseudomonas aeruginosa represents an extreme example. The objective of the study was to overcome the intrinsic resistance of P. aeruginosa by combining silver nanoparticles (AgNPs) with secondary metabolites from selected carnivorous plant species. We employed the broth microdilution method, the checkerboard titration technique and comprehensive phytochemical analyses to define interactions between nanoparticles and active compounds from carnivorous plants. It has been confirmed that P. aeruginosa is resistant to a broad range of secondary metabolites from carnivorous plants, i.e., naphthoquinones, flavonoids, phenolic acids (MBC = 512 µg mL−1) and only weakly sensitive to their mixtures, i.e., extracts and extracts’ fractions. However, it was shown that the antimicrobial activity of extracts and fractions with a significant level of naphthoquinone (plumbagin) was significantly enhanced by AgNPs. Our studies clearly demonstrated a crucial role of naphthoquinones in AgNPs and extract interaction, as well as depicted the potential of AgNPs to restore the bactericidal activity of naphthoquinones towards P. aeruginosa. Our findings indicate the significant potential of nanoparticles to modulate the activity of selected secondary metabolites and revisit their antimicrobial potential towards human pathogenic bacteria. 相似文献
9.
The interaction of nitric oxide with Ce0.75Zr0.25O2 solid solution were investigated by means of EPR and IR spectroscopies. The influence of adsorption parameters such as adsorption temperature and pressure, presence of the O2 co-reactant on the nature and relative surface abundance of the resultant mono- and dimeric NO species was elucidated. The thermal stability of the surface nitrosyl complexes and their reactivity toward dioxygen were also examined. 相似文献
10.
Michael J. Banach Stephen J. Clarson Gregory Beaucage Jason Benkoski Tom Mates Edward J. Kramer Richard A. Vaia 《应用聚合物科学杂志》2002,86(8):2021-2024
For many microelectronic and optoelectronic applications, polymer thin films require the addition of small molecules. However, the thin‐film geometry and associated processing techniques will influence the final morphology and compositional distribution of the constituents. It is therefore important that these be examined directly rather than inferred from bulk measurements. As an example system, the concentration and distribution of Disperse Red 1 (DR1) molecules in poly(methyl methacrylate) thin films were examined. Ultraviolet visibility spectroscopy and dynamic secondary ion mass spectrometry indicate that the composition of the molecules decreased dramatically with thermal treatment of the film. The sublimation of the chromophore was observed to occur at temperatures well below the melting point of the small molecule and the glass transition of the pure polymer; this solute loss manifested itself in changes in the glass transition temperature of the film. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2021–2024, 2002 相似文献