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881.
Epitope imprinting of iron binding protein of Neisseria meningitidis bacteria through multiple monomers imprinting approach 下载免费PDF全文
Neha Gupta Roop Shikha Singh Kavita Shah Rajniti Prasad Meenakshi Singh 《Journal of molecular recognition : JMR》2018,31(7)
Epitope imprinting is a promising technique for fabrication of novel diagnostic tools. In this study, an epitope imprinted methodology for recognition of target epitope sequence as well as targeted protein infused by bacterial infection in blood samples of patients suffering from brain fever is developed. Template sequence chosen is a ferric iron binding fbp A protein present in Neisseria meningitidis bacteria. To orient the imprinting template peptide sequence on gold surface of electrochemical quartz crystal microbalance (EQCM), thiol chemistry was utilized to form the self‐assembled monolayer on EQCM electrode. Here, synergistic effects induced by various noncovalent interactions extended by multiple monomers (3‐sulfopropyl methacrylate potassium‐salt and benzyl methacrylate) were used in fabricating the imprinting polymeric matrix with additional firmness provided by N,N‐methylene‐bis‐acrylamide as cross‐linker and azo‐isobutyronitrile as initiator. Extraction of template molecule was carried out with phosphate buffer solution. After extraction of epitope molecules from the polymeric film, epitope molecularly imprinted polymeric films were fabricated on EQCM electrode surface. Nonimprinted polymers were also synthesized in the similar manner without epitope molecule. Detection limit of epitope molecularly imprinted polymers and imprinting factor (epitope molecularly imprinted polymers/nonimprinted polymers) was calculated 1.39 ng mL?1 and 12.27 respectively showing high binding capacity and specific recognition behavior toward template molecule. Simplicity of present method would put forward a fast, facile, cost‐effective diagnostic tool for mass health care. 相似文献
882.
883.
SurePath® LBC improves the diagnostic accuracy of intrahepatic and hilar cholangiocarcinoma 下载免费PDF全文
884.
Wenming Wang Yaqin Zhao Hongfei Wang Bingsheng Yang 《Protein science : a publication of the Protein Society》2018,27(6):1102-1108
Centrin is a member of the EF‐hand superfamily of calcium‐binding proteins, a highly conserved eukaryotic protein that binds to Ca2+. Its self‐assembly plays a causative role in the fiber contraction that is associated with the cell division cycle and ciliogenesis. In this study, the crystal structure of N‐terminal domain of ciliate Euplotes octocarinatus centrin (N‐EoCen) was determined by using the selenomethionine single‐wavelength anomalous dispersion method. The protein molecules formed homotrimers. Every protomer had two putative Ca2+ ion‐binding sites I and II, protomer A, and C bound one Ca2+ ion, while protomer B bound two Ca2+ ions. A novel binding site III was observed and the Ca2+ ion was located at the center of the homotrimer. Several hydrogen bonds, electrostatic, and hydrophobic interactions between the protomers contributed to the formation of the oligomer. Structural studies provided insight into the foundation for centrin aggregation and the roles of calcium ions. 相似文献
885.
《Protein science : a publication of the Protein Society》2018,27(8):1439-1449
Flavodoxins (Flds) are small proteins that shuttle electrons in a range of reactions in microorganisms. Flds contain a redox‐active cofactor, a flavin mononucleotide (FMN), and it is well established that when Flds are reduced by one electron, a peptide bond close to the FMN isoalloxazine ring flips to form a new hydrogen bond with the FMN N5H, stabilizing the one‐electron reduced state. Here, we present high‐resolution crystal structures of Flavodoxin 1 from Bacillus cereus in both the oxidized (ox) and one‐electron reduced (semiquinone, sq) state. We observe a mixture of conformers in the oxidized state; a 50:50 distribution between the established oxidized conformation where the peptide bond is pointing away from the flavin, and a conformation where the peptide bond is pointing toward the flavin, approximating the conformation in the semiquinone state. We use single‐crystal spectroscopy to demonstrate that the mixture of conformers is not caused by radiation damage to the crystal. This is the first time that such a mixture of conformers is reported in a wild‐type Fld. We therefore carried out a survey of published Fld structures, which show that several proteins have a pronounced conformational flexibility of this peptide bond. The degree of flexibility seems to be modulated by the presence, or absence, of stabilizing interactions between the peptide bond carbonyl and its surrounding amino acids. We hypothesize that the degree of conformational flexibility will affect the Fld ox/sq redox potential. 相似文献
886.
Crystal structure of peptidoglycan recognition protein SA in Apis mellifera (Hymenoptera: Apidae) 下载免费PDF全文
Yanjie Liu Xiaomeng Zhao Muhammad Naeem Jiandong An 《Protein science : a publication of the Protein Society》2018,27(4):893-897
Peptidoglycan recognition protein SA (PGRP‐SA) is a key pattern recognition receptor in the insect innate immune system. PGRP‐SA can bind to bacterial PGN and activate the Toll pathway, which triggers the expression and release of antimicrobial peptides to prevent bacterial infection. Here, we report the first structure of Apis mellifera PGRP‐SA from Hymenoptera at 1.86 Å resolution. The overall architecture of Am‐PGRP‐SA was similar to the Drosophila PGRP‐SA; however, the residues involved in PGN binding groove were not conserved, and the binding pocket was narrower. This structure gives insight into PGN binding characteristics in honeybees. 相似文献
887.
对来源于枯草芽孢杆菌菌株168(Bacillus subtilis 168)的壳聚糖酶编码基因进行了序列优化及全合成,并在毕赤酵母(Pichia pastoris)中实现了分泌表达,表达产物的蛋白质浓度达到0.30mg/ml。表达的壳聚糖酶最适p H为5.6,最适温度为55℃,比酶活达84.54U/ml。该酶在50℃及以下较稳定。利用该酶水解低脱乙酰度壳聚糖并使用超高效液相色谱-四极杆飞行时间质谱(ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry,UPLC-QTOF MS)对产物的组分进行了分离及鉴定。根据一级质谱信息,推测酶解产物中包含至少37种聚合度2~18,不同脱乙酰度的壳寡糖组分。综上,利用毕赤酵母分泌表达了来源于枯草芽孢杆菌菌株168的壳聚糖酶基因,利用表达产物水解制备了低脱乙酰度壳寡糖并对其组分进行了分析,可为后续壳寡糖结构与功能关系的研究提供参考。 相似文献
888.
889.
Tissue oximetry by diffusive reflective visible light spectroscopy: Comparison of algorithms and their robustness 下载免费PDF全文
It is essential to measure tissue oxygen saturation (StO2) locally and in thin layers of tissue, for example, the bronchial mucosa, skin flaps and small bones. Visible light spectroscopy (VLS) with a shallow penetration depth is suitable method. Although several VLS algorithms have been developed and described, they have not yet been compared to each other. This hinders attempts to compare the clinical results obtained by different algorithms. To address this issue, we compared the algorithms of Harrison, Knoefel, Pittman‐Duling, Sato and our OxyVLS oximeter, which applies the algorithm from Wodick and Lübbers, in a liquid phantom with optical properties of human tissue. We generally observed considerable differences between the algorithms, which were StO2 dependent. Exceptions were OxyVLS and Sato, showing a high level of agreement with negligible StO2 dependency. In spite of the considerable deviation between the other algorithms, the difference of StO2 between them in clinically normal StO2 was <10%. We did not observe any dependency of the algorithms on hemoglobin content of the phantom or temperature. 相似文献
890.
Comments on recent reports on infrared spectral detection of disease markers in blood components 下载免费PDF全文
Max Diem 《Journal of biophotonics》2018,11(7)
The search for disease markers in whole blood, or easily accessible blood components by spectral methods is a highly important aspect in the field of biophotonic research for disease diagnostics and screening, since it promises a minimally invasive approach to assess an individual's state of health. Fourier transform infrared spectroscopy, in particular, promises to be a fast, inexpensive method to search for markers of disease, since it detects variation in the proteome, lipidome and metabolome of biofluids, or activation of immune cells. However, the analysis of any materials by spectral methods is confounded by external factors such as those related to sample deposition and data acquisition, and by inherent variations in blood plasma concentration of small molecules (lactate, carbonate, phosphate, glucose) that varies between individual subjects and even for a given individual, as a function of time. Furthermore, observed differences in spectral patterns between patient samples and the control group may be due to the body's immune response (in particular, to the albumin to globulin ratio) and therefore, may not be specific to disease. These factors need to be accounted for in any effort to reliably detect much smaller variations in the concentration of disease‐specific markers. 相似文献