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91.
Filamentous growth is a microbial differentiation response that involves the concerted action of multiple signaling pathways. In budding yeast, one pathway that regulates filamentous growth is a Cdc42p-dependent mitogen-activated protein kinase (MAPK) pathway. Several transmembrane (TM) proteins regulate the filamentous growth pathway, including the signaling mucin Msb2p, the tetraspan osmosensor Sho1p, and an adaptor Opy2p. The TM proteins were compared to identify common and unique features. Msb2p, Sho1p, and Opy2p associated by coimmunoprecipitation analysis but showed predominantly different localization patterns. The different localization patterns of the proteins resulted in part from different rates of turnover from the plasma membrane (PM). In particular, Msb2p (and Opy2p) were turned over rapidly compared to Sho1p. Msb2p signaled from the PM, and its turnover was a rate-limiting step in MAPK signaling. Genetic analysis identified unique phenotypes of cells overexpressing the TM proteins. Therefore, each TM regulator of the filamentous growth pathway has its own regulatory pattern and specific function in regulating filamentous growth. This specialization may be important for fine-tuning and potentially diversifying the filamentation response. 相似文献
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Adhikari AN Peng J Wilde M Xu J Freed KF Sosnick TR 《Protein science : a publication of the Protein Society》2012,21(1):107-121
Template-based methods for predicting protein structure provide models for a significant portion of the protein but often contain insertions or chain ends (InsEnds) of indeterminate conformation. The local structure prediction "problem" entails modeling the InsEnds onto the rest of the protein. A well-known limit involves predicting loops of ≤12 residues in crystal structures. However, InsEnds may contain as many as ~50 amino acids, and the template-based model of the protein itself may be imperfect. To address these challenges, we present a free modeling method for predicting the local structure of loops and large InsEnds in both crystal structures and template-based models. The approach uses single amino acid torsional angle "pivot" moves of the protein backbone with a C(β) level representation. Nevertheless, our accuracy for loops is comparable to existing methods. We also apply a more stringent test, the blind structure prediction and refinement categories of the CASP9 tournament, where we improve the quality of several homology based models by modeling InsEnds as long as 45 amino acids, sizes generally inaccessible to existing loop prediction methods. Our approach ranks as one of the best in the CASP9 refinement category that involves improving template-based models so that they can function as molecular replacement models to solve the phase problem for crystallographic structure determination. 相似文献
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Parajuli D Adhikari CR Kawakita H Yamada S Ohto K Inoue K 《Bioresource technology》2009,100(2):1000-1002
Recovery of Au(III) from hydrochloric acid medium by using crosslinked chestnut pellicle (CCP) gel was studied. Strong selectivity was observed for Au(III) showing negligible affinity for other precious metals and some base metal ions tested. The adsorption isotherm study exhibited the maximum loading capacity of the gel as high as 10.6 mol or about 2.1 kg gold per kg dry weight of gel. The reduction of Au(III) ion to elemental form during adsorption process is expected to be the reason of high selectivity and high capacity for Au(III). Kinetic studies at various temperatures confirm an endothermic adsorption process following the pseudo-first order rate law. 相似文献
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Priyanka Saha Sarmistha Sen Raychaudhuri Mathummal Sudarshan Anindita Chakraborty 《Biological trace element research》2010,135(1-3):283-294
Energy dispersive X-ray fluorescence (ED-XRF) technique has been used for the determination of trace element profile during different developmental stages of somatic embryogenic callus of an economically important medicinal plant, Plantago ovata Forssk. Somatic embryogenesis is a plant tissue culture-based technique, which is used for plant regeneration and crop improvement. In the present investigation, elemental content was analysed using ED-XRF technique during different developmental stages and also determine the effect of additives—casein hydrolysate and coconut water on the trace elemental profile of embryogenic callus tissue of P. ovata. Subsequent experiments showed significant alteration in the concentration of K, Ca, Mn, Fe, Zn, Cu, Br, and Sr in both the embryogenic and non-embryogenic callus. Higher K, Ca, Fe, Cu, and Zn accumulation was in embryogenic tissue stage compared to other stages, suggesting these elements are crucial for successful embryogenesis. The results suggest that this information could be useful for formulating a media for in vitro embryo induction of P. ovata. 相似文献
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Deuterium solid-state NMR spectroscopy was used to qualitatively study the effects of both 1-palmitoyl-2-linoleoyl-sn-glycero-3-phosphatidylcholine (PLiPC) and cholesterol on magnetically aligned phospholipid bilayers (bicelles) as a function of temperature utilizing the chain-perdeuterated probe 1,2-dimyristoyl-sn-glycero-3-phosphatidylcholine (DMPC-d54) in DMPC/dihexanoylPC (DHPC) phospholipid bilayers. The results demonstrate that polyunsaturated PC and cholesterol were successfully incorporated into DMPC/DHPC phospholipid bilayers, leading to a bicelle that will be useful for investigations of eukaryotic membrane protein-lipid interactions. The data indicate that polyunsaturated PC increases membrane fluidity and decreases the minimum magnetic alignment temperature for DMPC/DHPC bicelles. Conversely, the introduction of cholesterol into aligned DMPC/DHPC bilayers decreases fluidity in the membrane and increases the minimum temperature necessary to magnetically align the phospholipid bilayers. Finally, the addition of Tm3+ to magnetically aligned DMPC/DMPC-d54/PLiPC/DHPC bilayers doubles the quadrupolar splittings, indicating that this unique bicelle system can be aligned with the bilayer normal parallel to the static magnetic field. 相似文献