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991.
992.
Weiduan Xu Jianmin Chen Glenn Yamasaki John E. Murphy Baisong Mei 《Molecular biotechnology》2010,45(3):248-256
Many therapeutic proteins require appropriate glycosylation for their biological activities and plasma half life. Coagulation
factor VIII (FVIII) is a glycoprotein which has extensive post-translational modification by N-linked glycosylation. The terminal
sialic acid in the N-linked glycans of FVIII is required for maximal circulatory half life. The extent of FVIII sialylation
can be determined by high pH anion-exchange chromatography coupled with a pulse electrochemical detector (HPAEC-PED), but
this requires a large amount of purified protein. Using FVIII as a model, the objective of the present study was to develop
assays that enable detection and prediction of sialylation deficiency at an early stage in the process and thus prevent downstream
product quality excursions. Lectin ECA (Erythrina Cristagalli) binds to unsialylated Galβ1-4 GlcNAc and the ECA-binding level (i.e., terminal Gal(β1-4) exposure) is inversely proportional
to the level of sialylation. By using ECA, a cell-based assay was developed to measure the global sialylation profile in FVIII
producing cells. To examine the Galβ1-4 exposure on the FVIII molecule in bioreactor tissue culture fluid (TCF), an ELISA-based
ECA-FVIII binding assay was developed. The ECA-binding specificity in both assays was assessed by ECA-specific sugar inhibitors
and neuraminidase digestion. The ECA-binding specificity was also independently confirmed by a ST3GAL4 siRNA knockdown experiment.
To establish the correlation between Galβ1-4 exposure and the HPAEC-PED determined FVIII sialylation value, the FVIII containing
bioreactor TCF and the purified FVIII samples were tested with ECA ELISA binding assay. The results indicated an inverse correlation
between ECA binding and the corresponding HPAEC-PED sialylation value. The ECA-binding assays are cost effective and can be
rapidly performed, thereby making them effective for in-process monitoring of protein sialylation. 相似文献
993.
994.
Shi-Liang Zhou Xin-Hui Zou Zhi-Qin Zhou Jing Liu Chao Xu Jing Yu Qiang Wang Da-Ming Zhang Xiao-Quan Wang Song Ge Tao Sang Kai-Yu Pan De-Yuan Hong 《Proceedings. Biological sciences / The Royal Society》2014,281(1797)
The origin of cultivated tree peonies, known as the ‘king of flowers'' in China for more than 1000 years, has attracted considerable interest, but remained unsolved. Here, we conducted phylogenetic analyses of explicitly sampled traditional cultivars of tree peonies and all wild species from the shrubby section Moutan of the genus Paeonia based on sequences of 14 fast-evolved chloroplast regions and 25 presumably single-copy nuclear markers identified from RNA-seq data. The phylogeny of the wild species inferred from the nuclear markers was fully resolved and largely congruent with morphology and classification. The incongruence between the nuclear and chloroplast trees suggested that there had been gene flow between the wild species. The comparison of nuclear and chloroplast phylogenies including cultivars showed that the cultivated tree peonies originated from homoploid hybridization among five wild species. Since the origin, thousands of cultivated varieties have spread worldwide, whereas four parental species are currently endangered or on the verge of extinction. The documentation of extensive homoploid hybridization involved in tree peony domestication provides new insights into the mechanisms underlying the origins of garden ornamentals and the way of preserving natural genetic resources through domestication. 相似文献
995.
Journal of Physiology and Biochemistry - Atherosclerosis is one common chronic inflammatory disease in which angiogenesis is involved. Here we established an in vitro cell model of angiogenesis... 相似文献
996.
Ming Xu Vladimir V. Ermolenkov Vladimir N. Uversky Igor K. Lednev 《Journal of biophotonics》2008,1(3):215-229
Amyloid fibrils are associated with numerous degenerative diseases. The molecular mechanism of the structural transformation of native protein to the highly ordered cross‐β structure, the key feature of amyloid fibrils, is under active investigation. Conventional biophysical methods have limited application in addressing the problem because of the heterogeneous nature of the system. In this study, we demonstrated that deep‐UV resonance Raman (DUVRR) spectroscopy in combination with circular dichroism (CD) and intrinsic tryptophan fluorescence allowed for quantitative characterization of protein structural evolution at all stages of hen egg white lysozyme fibrillation in vitro. DUVRR spectroscopy was found to be complimentary to the far‐UV CD because it is (i) more sensitive to β ‐sheet than to α ‐helix, and (ii) capable of characterizing quantitatively inhomogeneous and highly light‐scattering samples. In addition, phenylalanine, a natural DUVRR spectroscopic biomarker of protein structural rearrangements, exhibited substantial changes in the Raman cross section of the 1000‐cm–1 band at various stages of fibrillation. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
997.
Genome-scale models of metabolism have only been analyzed with the constraint-based modelling philosophy and there have been several genome-scale gene-protein-reaction models. But research on the modelling for energy metabolism of organisms just began in recent years and research on metabolic weighted complex network are rare in literature. We have made three research based on the complete model of E. coli’s energy metabolism. We first constructed a metabolic weighted network using the rates of free energy consumption within metabolic reactions as the weights. We then analyzed some structural characters of the metabolic weighted network that we constructed. We found that the distribution of the weight values was uneven, that most of the weight values were zero while reactions with abstract large weight values were rare and that the relationship between w (weight values) and v (flux values) was not of linear correlation. At last, we have done some research on the equilibrium of free energy for the energy metabolism system of E. coli. We found that (free energy rate input from the environment) can meet the demand of (free energy rate dissipated by chemical process) and that chemical process plays a great role in the dissipation of free energy in cells. By these research and to a certain extend, we can understand more about the energy metabolism of E. coli. 相似文献
998.
999.
Yao He Hui Xu Zichao Xiang Hongyou Yu Li Xu Yongwen Guo Ye Tian Rui Shu Xianrui Yang Chaoran Xue Mengyuan Zhao Yiruo He Xianglong Han Ding Bai 《Journal of cellular physiology》2019,234(4):5086-5096
During orthodontic tooth movement (OTM), periodontal ligament cells (PDLCs) receive the mechanical stimuli and transform it into myofibroblasts (Mfbs). Indeed, previous studies have demonstrated that mechanical stimuli can promote the expression of Mfb marker α-smooth muscle actin (α-SMA) in PDLCs. Transforming growth factor β1 (TGF-β1), as the target gene of yes-associated protein (YAP), has been proven to be involved in this process. Here, we sought to assess the role of YAP in Mfbs differentiation from PDLCs. The time-course expression of YAP and α-SMA was manifested in OTM model in vivo as well as under tensional stimuli in vitro. Inhibition of RhoA/Rho-associated kinase (ROCK) pathway using Y27632 significantly reduced tension-induced Mfb differentiation and YAP expression. Moreover, overexpression of YAP with lentiviral transfection in PDLCs rescued the repression effect of Mfb differentiation induced by Y27632. These data together suggest a crucial role of YAP in regulating tension-induced Mfb differentiation from PDLC interacted with RhoA/ROCK pathway. 相似文献
1000.
Longhe Xu Felipe Matsunaga Jin Xi Min Li Jingyuan Ma 《Journal of biomolecular structure & dynamics》2013,31(11):1833-1840
We recently demonstrated that the anionic detergent sodium dodecyl sulfate (SDS) specifically interacts with the anesthetic binding site in horse spleen apoferritin, a soluble protein which models anesthetic binding sites in receptors. This raises the possibility of other detergents similarly interacting with and occluding such sites from anesthetics, thereby preventing the proper identification of novel anesthetic binding sites. n-Dodecyl β-D-maltoside (DDM) is a non-ionic detergent commonly used during protein-anesthetic studies because of its mild and non-denaturing properties. In this study, we demonstrate that SDS and DDM occupy anesthetic binding sites in the model proteins human serum albumin (HSA) and horse spleen apoferritin and thereby inhibit the binding of the general anesthetics propofol and isoflurane. DDM specifically interacts with HSA (Kd?=?40?μM) with a lower affinity than SDS (Kd?=?2?μM). DDM exerts all these effects while not perturbing the native structures of either model protein. Computational calculations corroborated the experimental results by demonstrating that the binding sites for DDM and both anesthetics on the model proteins overlapped. Collectively, our results indicate that DDM and SDS specifically interact with anesthetic binding sites and may thus prevent the identification of novel anesthetic sites. Special precaution should be taken when undertaking and interpreting results from protein-anesthetic investigations utilizing detergents like SDS and DDM. 相似文献