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An insect larval toxin designated CryII is produced by several subspecies of Bacillus thuringiensis and differs from the other major delta-endotoxins in these bacteria in its size, toxicity profile and presence as part of an operon with three open reading frames (ORF). Such an operon from a novel B. thuringiensis isolate has been cloned and differs from one previously characterized in the following ways: (a) the size and number of amino acid repeats in one of the ORFs; (b) the smaller size of the CryII protoxin and the presence of a unique 110-kDa CryII-related antigen; and (c) high larvicidal activity for a particular Lepidopteran but low activity for a Dipteran. Various subclones of this operon were introduced into a plasmid-free B. thuringiensis strain and only the cryII gene was found to be necessary for protoxin accumulation. 相似文献
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H Cao L Bangalore C Dompé B J Bormann D F Stern 《The Journal of biological chemistry》1992,267(28):20489-20492
The neu proto-oncogene encodes a receptor tyrosine kinase (p185) that is closely related to the epidermal growth factor receptor. It has been proposed that receptor tyrosine kinases are activated through oligomerization. Because this clustering model predicts that oligomerization of receptors is sufficient to activate them, we determined if p185 can be activated by introducing an extra cysteine proximal to the transmembrane domain. This should induce inter-receptor disulfide bonding and, according to the clustering model, activate the receptor. This amino acid substitution enhanced recovery of both normal and transforming neu proteins as dimers, with normal p185 recovered predominantly as monomers and transforming p185* as dimers. However, the cysteine substitution did not affect the transforming activity of the two proteins. 相似文献
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Zhan-Qi Dong Nan Hu Jun Zhang Ting-Ting Chen Ming-Ya Cao Hai-Qing Li Xue-Jiao Lei Peng Chen Cheng Lu Min-Hui Pan 《PloS one》2015,10(12)
We have previously reported that baculovirus Bombyx mori nucleopolyhedrovirus (BmNPV) late expression factor 11 (lef-11) is associated with viral DNA replication and have demonstrated that it potentially interacts with itself; however, whether LEF-11 forms oligomers and the impact of LEF-11 oligomerization on viral function have not been substantiated. In this study, we first demonstrated that LEF-11 is capable of forming oligomers. Additionally, a series of analyses using BmNPV LEF-11 truncation mutants indicated that two distinct domains control LEF-11 oligomerization (aa 42–61 and aa 72–101). LEF-11 truncation constructs were inserted into a lef-11-knockout BmNPV bacmid, which was used to demonstrate that truncated LEF-11 lacking either oligomerization domain abrogates viral DNA replication. Finally, site-directed mutagenesis was used to determine that the conserved hydrophobic residues Y58&I59 (representing Y58 and I59), I85 and L88&L89 (representing L88 and L89) are required for LEF-11 oligomerization and viral DNA replication. Collectively, these data indicate that BmNPV LEF-11 oligomerization influences viral DNA replication. 相似文献
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Juan Du Yan Cao Qian Wang Nana Zhang Xiaoyu Liu Dandan Chen Xiaoyun Liu Qunyuan Xu Wei Ma 《Cell cycle (Georgetown, Tex.)》2015,14(22):3566-3579
Polo-like kinase 1 (Plk1) is pivotal for proper mitotic progression, its targeting activity is regulated by precise subcellular positioning and phosphorylation. Here we assessed the protein expression, subcellular localization and possible functions of phosphorylated Plk1 (pPlk1Ser137 and pPlk1Thr210) in mouse oocytes during meiotic division. Western blot analysis revealed a peptide of pPlk1Ser137 with high and stable expression from germinal vesicle (GV) until metaphase II (MII), while pPlk1Thr210 was detected as one large single band at GV stage and 2 small bands after germinal vesicle breakdown (GVBD), which maintained stable up to MII. Immunofluorescence analysis showed pPlk1Ser137 was colocalized with microtubule organizing center (MTOC) proteins, γ-tubulin and pericentrin, on spindle poles, concomitantly with persistent concentration at centromeres and dynamic aggregation between chromosome arms. Differently, pPlk1Thr210 was persistently distributed across the whole body of chromosomes after meiotic resumption. The specific Plk1 inhibitor, BI2536, repressed pPlk1Ser137 accumulation at MTOCs and between chromosome arms, consequently disturbed γ-tubulin and pericentrin recruiting to MTOCs, destroyed meiotic spindle formation, and delayed REC8 cleavage, therefore arresting oocytes at metaphase I (MI) with chromosome misalignment. BI2536 completely reversed the premature degradation of REC8 and precocious segregation of chromosomes induced with okadaic acid (OA), an inhibitor to protein phosphatase 2A. Additionally, the protein levels of pPlk1Ser137 and pPlk1Thr210, as well as the subcellular distribution of pPlk1Thr210, were not affected by BI2536. Taken together, our results demonstrate that Plk1 activity is required for meiotic spindle assembly and REC8 cleavage, with pPlk1Ser137 is the action executor, in mouse oocytes during meiotic division. 相似文献
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Yao Chen Jie Zhu Jun Mo Hongyu Yang Xueyang Jiang Hongzhi Lin 《Journal of enzyme inhibition and medicinal chemistry》2018,33(1):290-302
Small molecule cholinesterases inhibitor (ChEI) provides an effective therapeutic strategy to treat Alzheimer’s disease (AD). Currently, the discovery of new ChEI with multi-target effect is still of great importance. Herein, we report the synthesis, structure–activity relationship study and biological evaluation of a series of tacrine-cinnamic acid hybrids as new ChEIs. All target compounds are evaluated for their in vitro cholinesterase inhibitory activities. The representatives which show potent activity on cholinesterase, are evaluated for the amyloid β-protein self-aggregation inhibition and in vivo assays. The optimal compound 19, 27, and 30 (human AChE IC50?=?10.2?±?1.2, 16.5?±?1.7, and 15.3?±?1.8?nM, respectively) show good performance in ameliorating the scopolamine-induced cognition impairment and preliminary safety in hepatotoxicity evaluation. These compounds deserve further evaluation for the development of new therapeutic agents against AD. 相似文献
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