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101.
1H NMR studies of lambda cro repressor. 2. Sequential resonance assignments of the 1H NMR spectrum 总被引:1,自引:0,他引:1
The cro repressor protein from bacteriophage lambda has been studied in solution by two-dimensional nuclear magnetic resonance spectroscopy (2D NMR). Following the approach of Wüthrich and co-workers [Wüthrich, K., Wider, G., Wagner, G., & Braun, W. (1982) J. Mol. Biol. 155, 311-319], individual spin systems were identified by J-correlated spectroscopy (COSY) supplemented, where necessary, by relayed coherence transfer spectroscopy (RELAY). Nuclear Overhauser effect spectroscopy (NOESY) was used to obtain sequence-specific assignments. From the two-dimensional spectra, the peptide backbone resonances (NH and C alpha H) for 65 of the 66 amino acids were assigned, as well as most of the side chain resonances. The chemical shifts for the assigned protons are reported at 35 degrees C in 10 mM potassium phosphate, pH 6.8, and in 10 mM potassium phosphate, pH 4.6, 0.2 M KCl, and 0.1 mM EDTA. Small shifts were observed for some resonances upon addition of salt, but no major changes in the spectrum were seen, indicating that no global structural change occurs between these ionic strengths. NOE patterns characteristic of alpha-helices, beta-strands, and turns are seen in various regions of the primary sequence. From the location of these regions the secondary structure of cro in solution appears to be virtually identical with the crystal structure [Anderson, W. F., Ohlendorf, D. H., Takeda, Y., & Matthews, B. W. (1981) Nature (London) 290, 754-758]. Missing assignments include the Pro-59 resonances and the peripheral protons of the eight lysine, the three arginine, and three of the five isoleucine residues. 相似文献
102.
Patricia C. Weber F.R. Salemme Spencer H. Lin Yasuo Konishi H.A. Scheraga 《Journal of molecular biology》1985,181(3):453
A cross-linked derivative of ribonuclease A, Nε,Nε′-(2,4-dinitrophenylene-1,5)-(lysine7-lysine41)-RNase A, has been crystallized by dialysis against 30% () ethanol/water mixtures buffered at high pH. Single crystals belong to the orthorhombic space group P212121, , with one molecule in the Crystallographic asymmetric unit. 相似文献
103.
Effects of Nitrate Application on Amaranthus powellii Wats. : I. Changes in Photosynthesis, Growth Rates, and Leaf Area 总被引:4,自引:2,他引:2 下载免费PDF全文
Physiological effects of different nitrate applications were studied using the C4 plant, Amaranthus powellii Wats. Plants were grown in a controlled environment chamber and watered daily with nutrient solutions containing 45, 10, 5, or 1 millimolar nitrate. Chloride and sulfate were used to keep the cation and phosphate concentrations constant. Total leaf nitrogen concentration, chlorophyll concentration, specific leaf mass, leaf area, relative growth rate, relative leaf growth rate, unit leaf rate (increase of dry mass per unit leaf area per day), net photosynthetic rate, and incident quantum yield decreased with decreasing nitrate concentration. The per cent decrease of unit leaf rate was similar to the decrease of light-saturated net photosynthetic rate; however, the decrease in relative growth rate was less than that of unit leaf rate because leaf area ratio (leaf area per unit dry mass) increased with decreasing nitrate concentration. Essential mineral concentrations per unit leaf area were about equal among all treatments. Leaf expansion, determined by stomatal density, decreased except for the 1 millimolar treatment which showed relatively more cell expansion but less cell division. Decreased nitrate application was correlated with higher osmotic potentials and lower pressure potentials (determined by pressure-volume curves), whereas leaf water potentials were equal among treatments. Even though total leaf area and shoot mass decreased with decreasing applied nitrate, the increase of the leaf area ratio may be related to selection for the highest possible growth rate. 相似文献
104.
105.
T Patrice B Dreno J Weber L Le Bodic H Barriere 《Plastic and reconstructive surgery》1985,76(4):554-557
The argon laser, which has been proven both useful and safe for port-wine stain therapy, interacts with the hemoglobin of the vessels. In a percentage of cases, this treatment is still inefficient, and there is a lack of correlation between these bad results and clinical or histologic criteria. Thermography, which explores the vascularization of the port-wine stain, leads us to consider port-wine stains from a physical point of view. This very simple test shows no correlation with the clinical parameters of port-wine stain but is closely related to the results obtained with laser therapy. It seems to be a good criterion to estimate the argon laser treatment prognosis. 相似文献
106.
A restriction enzyme map of the IncFI plasmid ColV2-K94 was generated using EcoRI, BamHI, HindIII, and XhoI; the genetic features of this element were then mapped from previous heteroduplex studies. 相似文献
107.
The regulatory chain in the p36-kd substrate complex of viral tyrosine-specific protein kinases is related in sequence to the S-100 protein of glial cells. 总被引:23,自引:5,他引:18 下载免费PDF全文
The major cytoplasmic target of various tyrosine-specific protein kinases is a 36-kd protein (p36). This protein can exist as a monomer or as a complex with a small subunit which seems to have a regulatory function. Amino acid sequence analysis of the small subunit from porcine intestine documents a unique polypeptide of 95 residues with a calculated mol. wt. close to 11 kd (p11). Since an immunologically related subunit of the same electrophoretic mobility is also found in the corresponding complex of chicken intestine p11 is well conserved across species. Unexpectedly, the sequence of p11 shows a high homology with the glia-specific protein S-100 whose biological function is not known. Although both proteins are dimers of rather small polypeptides we have not been able to detect in our preparations of p11 the moderate Ca2+ binding known for S-100. Certain implications of this sequence relation are discussed. 相似文献
108.
Guinea pigs and athymic nude (RNU/RNU) rats were used to assess the efficacy of three orally administered antifungal agents — Tolciclate, Tolnaftate, and Ketoconazole — against Trichophyton mentagrophytes dermatophytosis. All three antifungal agents inhibited the test strain of T. mentagrophytes in vitro. Antifungal agents were tested in intervention (oral therapy started 5 days after challenge) or prophylaxis (oral therapy started 5 days before challenge) protocols. Oral treatment of dermatophytosis on guinea pig skin demonstrated that Tolciclate and Tolnaftate alleviated clinical symptoms and shortened the duration of the dermatophytosis, in comparison to nontreated controls. Assessment of antifungal efficacy in the guinea pig model was time consuming (30–35 days) and variability in the duration and severity of clinical symptoms on guinea pig skin was common.Oral therapy of chronically infected athymic rats demonstrated that Tolciclate, Tolnaftate, and Ketoconazole were effective antifungal agents in vivo. Obvious improvement in clinical symptoms of dermatophytosis (i.e. less erythema and fewer lesions) was evident with all three antifungal agents within 10 days of starting oral therapy. By day 20, athymic rats that were treated with either Tolciclate or Ketoconazole showed marked clinical improvement of the chronic dermatophytosis.Chronically infected athymic rats, which lack thymus matured T-cells, are a promising new model to evaluate the efficacy of antifungal agents by culture, histology, and visual observations of clinical symptoms. 相似文献
109.
110.