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91.
92.
Structural basis for FGF receptor dimerization and activation. 总被引:25,自引:0,他引:25
The crystal structure of FGF2 bound to a naturally occurring variant of FGF receptor 1 (FGFR1) consisting of immunoglobulin-like domains 2 (D2) and 3 (D3) has been determined at 2.8 A resolution. Two FGF2:FGFR1 complexes form a 2-fold symmetric dimer. Within each complex, FGF2 interacts extensively with D2 and D3 as well as with the linker between the two domains. The dimer is stabilized by interactions between FGF2 and D2 of the adjoining complex and by a direct interaction between D2 of each receptor. A positively charged canyon formed by a cluster of exposed basic residues likely represents the heparin-binding site. A general model for FGF- and heparin-induced FGFR dimerization is inferred from the crystal structure, unifying a wealth of biochemical data. 相似文献
93.
Different Tyrosine Autophosphorylation Requirements in Fibroblast Growth Factor Receptor-1 Mediate Urokinase-Type Plasminogen Activator Induction and Mitogenesis 总被引:2,自引:1,他引:1
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Among the seven tyrosine autophosphorylation sites identified in the intracellular domain of tyrosine kinase fibroblast growth factor receptor-1 (FGFR1), five of them are dispensable for FGFR1-mediated mitogenic signaling. The possibility of dissociating the mitogenic activity of basic FGF (FGF2) from its urokinase-type plasminogen activator (uPA)-inducing capacity both at pharmacological and structural levels prompted us to evaluate the role of these autophosphorylation sites in transducing FGF2-mediated uPA upregulation. To this purpose, L6 myoblasts transfected with either wild-type (wt) or various FGFR1 mutants were evaluated for the capacity to upregulate uPA production by FGF2. uPA was induced in cells transfected with wt-FGFR1, FGFR1-Y463F, -Y585F, -Y730F, -Y766F, or -Y583/585F mutants. In contrast, uPA upregulation was prevented in L6 cells transfected with FGFR1-Y463/583/585/730F mutant (FGFR1–4F) or with FGFR1-Y463/583/585/730/766F mutant (FGFR1–5F) that retained instead a full mitogenic response to FGF2; however, preservation of residue Y730 in FGFR1-Y463/583/585F mutant (FGFR1–3F) and FGFR1-Y463/583/585/766F mutant (FGFR1–4Fbis) allows the receptor to transduce uPA upregulation. Wild-type FGFR1, FGFR1–3F, and FGFR1–4F similarly bind to a 90-kDa tyrosine-phosphorylated protein and activate Shc, extracellular signal-regulated kinase (ERK)2, and JunD after stimulation with FGF2. These data, together with the capacity of the ERK kinase inhibitor PD 098059 to prevent ERK2 activation and uPA upregulation in wt-FGFR1 cells, suggest that signaling through the Ras/Raf-1/ERK kinase/ERK/JunD pathway is necessary but not sufficient for uPA induction in L6 transfectants. Accordingly, FGF2 was able to stimulate ERK1/2 phosphorylation and cell proliferation, but not uPA upregulation, in L6 cells transfected with the FGFR1-Y463/730F mutant, whereas the FGFR1-Y583/585/730F mutant was fully active. We conclude that different tyrosine autophosphorylation requirements in FGFR1 mediate cell proliferation and uPA upregulation induced by FGF2 in L6 cells. In particular, phosphorylation of either Y463 or Y730, dispensable for mitogenic signaling, represents an absolute requirement for FGF2-mediated uPA induction. 相似文献
94.
Fakhrossadat Mohammadi Marzieh Moeeni 《Journal of biomolecular structure & dynamics》2017,35(16):3486-3498
It was reported that bovine α-lactalbumin (BLA) as an important whey protein can be utilized as valuable vehicle for metal ions. The goal of this study was to investigate the interaction of BLA with bisdemethoxycurcumin (BDMC), Diacetylcurcumin (DAC), and diacetylbisdemethoxycurcumin (DABC) as three bioactive compounds by fluorescence quenching measurements and docking studies. It was observed that these ligands come closer to tryptophan residues and quench their emission without any change in their micro region polarity. The Stern–Volmer equation which is the best model to provide information about the interaction between small bioactive molecules and proteins was used to obtain the binding constants and the binding stoichiometry. Information about the extent of resonance energy transfer and Förster’s distance between donor and acceptor was estimated. Thermodynamic parameters confirmed that the final BDMC–BLA complex was stabilized by hydrogen bonds, whereas the final DABC–BLA and DAC–BLA complexes were stabilized by hydrophobic bonds which are in accordance with their chemical structures. Both the synchronous and docking studies verified that theTrp-26 which is the most exposed Tryptophan residue has the most contribution in the binding process. The Förster’s distances between bound ligands and tryptophans were in agreement with the measured distances by docking studies. The obtained achievements confirmed that there are considerable binding interactions between these curcuminoids and BLA. 相似文献
95.
Bioprocess and Biosystems Engineering - In this article, availability and control of water in solid-state fermentation (SSF) were investigated. Based on passive transport of water through plasma... 相似文献
96.
97.
The problem of deterioration of art works is particularly relevant in countries like Iran that are rich in cultural heritage.
According to UNESCO data, Iran holds the tenth rank in a list of countries possessing the highest number of monuments belonging
to the world cultural heritage. Archaeological areas, buildings, mosques, statues, museums and objects are all exposed to
different biogenic and abiogenic stresses under generally aggressive climatic conditions. Lichens and fungi are known to actively
decompose stone surfaces. This process is both physical and chemical in nature and often reaches deep below the stone surfaces.
This is caused by chemical and physical interactions of the microbiota with the fluctuating and often drastically changing
environmental conditions. Here, we describe and analyze the mainly physical degradation by invading fungal hyphae between
stone crystals and a generally destabilizing stone texture. In addition to physical deterioration, organic acids produced
by lichens enhance the chemical decomposing processes. In this work, penetration of hyphal bundles as well as individual fungi
was studied, and the biodeteriorating patterns were documented and compared to general physical–chemical weathering phenomena.
Several strains of aggressive black yeast-like fungi and bacteria were isolated and cultivated and will be described in a
taxonomical context with many other isolates from different localities using physiological, morphological and molecular data. 相似文献
98.
Abdol-Khalegh Bordbar Fakhrossadat Mohammadi Chris Orvig 《Journal of inorganic biochemistry》2009,103(4):643-647
Bis(maltolato)oxovanadium(IV) (BMOV), and its ethylmaltol analog, bis(ethylmaltolato)oxovanadium(IV) (BEOV), are candidate insulin-enhancing agents for the treatment of type 2 diabetes mellitus; in mid-2008, BEOV advanced to phase II clinical testing. The interactions of BMOV and its inorganic congener, vanadyl sulfate (VOSO4), with human serum apo-transferrin (hTf) were investigated using differential scanning calorimetry (DSC). Addition of BMOV or VOSO4 to apo-hTf resulted in an increase in thermal stability of both the C- and N-lobes of transferrin as a result of binding to either vanadyl compound. A series of DSC thermograms of hTf solutions containing different molar ratios of BMOV and VOSO4 were used to determine binding constants; at 25 °C the binding constants of BMOV to the C- and N-lobes of apo-hTf were found to be 3 (±1) × 105 and 1.8 (±0.7) × 105 M−1, respectively. The corresponding values for VOSO4 were 1.7 (±0.3) × 105 and 7 (±2) × 104 M−1. The results show that the vanadium species initially presented as either BMOV or VOSO4 had similar affinities for human serum transferrin due to oxidation of solvated vanadyl(IV) prior to complexation to transferrin. Binding of metavanadate () was confirmed by DSC and isothermal titration calorimetry (ITC) experiments of the interaction between sodium metavanadate (NaVO3) and hTf. 相似文献
99.
Radovan Murín Ghasem Mohammadi Dieter Leibfritz Bernd Hamprecht 《Neurochemical research》2009,34(7):1195-1203
The three essential amino acids, valine, leucine and isoleucine, constitute the group of branched-chain amino acids (BCAAs).
BCAAs are rapidly taken up into the brain parenchyma, where they serve several distinct functions including that as fuel material
in brain energy metabolism. As one function of astrocytes is considered the production of fuel molecules that support the
energy metabolism of adjacent neural cells in brain. Astroglia-rich primary cultures (APC) were shown to rapidly dispose of
the BCAAs, including valine, contained in the culture medium. While the metabolisms of leucine and isoleucine by APC have
already been studied in detail, some aspects of valine metabolism remained to be determined. Therefore, in the present study
an NMR analysis was performed to identify the 13C-labelled metabolites that are generated by APC during catabolism of [U-13C]valine and that are subsequently released into the incubation medium. The results presented show that APC (1) are potently
disposing of the valine contained in the incubation medium; (2) are capable of degrading valine to the tricarboxylic acid
(TCA) cycle member succinyl-CoA; and (3) release into the extracellular milieu valine catabolites and compounds generated
from them such as [U-13C]2-oxoisovalerate, [U-13C]3-hydroxyisobutyrate, [U-13C]2-methylmalonate, [U-13C]isobutyrate, and [U-13C]propionate as well as several TCA cycle-dependent metabolites including lactate.
This article is dedicated to Dr. George DeVries. 相似文献
100.
Hamid Mohammadi Sandra Alaniz Zia Banihashemi Josep Armengol 《Journal of Phytopathology》2009,157(10):642-645
Eight Cylindrocarpon isolates recovered from the trunk bases of 10-year-old grapevines showing decline symptoms from two vineyards in Bavanat (Fars province, south-western Iran) were studied. Based on phenotypical characteristics, mating experiments and molecular data, they were identified as Cylindrocarpon liriodendri. Pathogenicity was confirmed with selected isolates inoculated into 8-month-old dormant rooted cuttings of grapevine rootstock cv. 110 Richter. This is the first report of C. liriodendri causing black foot disease of grapevines in Iran. 相似文献