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991.
Hualin Jiang Fangfang Zhong Lu Sun Weiyue Feng Zhong-Xian Huang Xiangshi Tan 《Amino acids》2011,40(4):1195-1204
The cytochrome P450 (CYP) superfamily plays a key role in the oxidative metabolism of a wide range of drugs and exogenous
chemicals. CYP2C8 is the principal enzyme responsible for the metabolism of the anti-cancer drug paclitaxel in the human liver.
Nearly all previous works about polymorphic variants of CYP2C8 were focused on unpurified proteins, either cells or human
liver microsomes; therefore their structure–function relationships were unclear. In this study, two polymorphic enzymes of
CYP2C8 (CYP2C8.4 (I264M) and CYP2C8 P404A) were expressed in E. coli and purified. Metabolic activities of paclitaxel by the two purified polymorphic enzymes were observed. The activity of CYP2C8.4
was 25% and CYP2C8 P404A was 30% of that of WT CYP2C8, respectively. Their structure–function relationships were systematically
investigated for the first time. Paclitaxel binding ability of CYP2C8.4 increased about two times while CYP2C8 P404A decreased
about two times than that of WT CYP2C8. The two polymorphic mutant sites of I264 and P404, located far from active site and
substrate binding sites, significantly affect heme and/or substrate binding. This study indicated that two important nonsubstrate
recognition site (SRS) residues of CYP2C8 are closely related to heme binding and/or substrate binding. This discovery could
be valuable for explaining clinically individual differences in the metabolism of drugs and provides instructed information
for individualized medication. 相似文献
992.
Carbon dots as a luminescence sensor for ultrasensitive detection of phosphate and their bioimaging properties 下载免费PDF全文
Jingyi Xu Ying Zhou Guifang Cheng Meiting Dong Shuxian Liu Chaobiao Huang 《Luminescence》2015,30(4):411-415
Highly blue fluorescence carbon dots were synthesized by one‐step hydrothermal treatment of potatoes. The as‐obtained C‐dots have been applied to bioimaging of HeLa cells, which shows their excellent biocompatibility and low cytotoxicity. The results reveal that C‐dots are promising for real cell imaging applications. In addition, the carbon dots can be utilized as a probe for sensing phosphate. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
993.
994.
葡萄叶绿体rbcL基因的结构分析 总被引:2,自引:0,他引:2
以玫瑰香葡萄(Vitisvinifera L.)为材料,克隆了含有叶绿体rbc L基因的3.1 kb Bam HⅠ片段,构建了该基因的限制性酶切图谱,测定了该基因的核苷酸序列。所测的核苷酸序列总长度为2004 bp,其中基因的编码区为1428 bp,编码一个含475 个氨基酸的蛋白质,其分子量约为53 kD;测定基因的5上游含启动子的部分共358 bp,包括- 10 区(TAAAAT)、- 35区(TTGCGC)和SD 序列(GGAGG);基因的3下游区共218 bp,含有3 个转录茎环终止结构。玫瑰香葡萄rbc L基因编码区的核苷酸序列与烟草、矮牵牛、菠菜、苜蓿、水稻和玉米之间的同源性分别为91.5% 、91.4% 、90.2% 、89.8% 、86.3% 和84.5% ;推导出的氨基酸序列的同源性分别为92.2% 、91.6% 、92.2% 、93.7% 、93.5% 和90.1% 。 相似文献
995.
秋茄(Kandelia candel)的区域性种群(population)遗传结构 总被引:4,自引:1,他引:4
在台湾北部淡水河河口沼泽地带的秋茄(水笔仔),依其林冠高度略可分成高、矮两个亚种群(Subpopulation)。矮生秋茄长在地面较高的河边,高生秋茄则沿着一条潮溪,长在较低处。使用淀粉凝胶方法研究同功酶组合型式,判断这个地区的区域种群的遗传结构,发现生长在沼泽区内较干燥地带的秋茄和长在潮湿地带的秋茄遗传上的分化程度很低(Fst= 0.043)。这可能是因为区内的基因流传很顺畅,抵消了可能发生的种群分化。 相似文献
996.
Five lacY mutants with amber stop codons at known positions were each placed into 12 different suppressor strains. The 60 amino acid substitutions obtained in this manner were tested for growth on lactose-minimal medium plates and for transport of lactose, melibiose, and thiomethylgalactoside. Most of the amino acid substitutions in the regions of the putative loops (between transmembrane alpha helices) resulted in a reasonable growth rate on lactose with moderate-to-good transport activity. In one strain (glycine substituted for Trp-10), abnormal sugar recognition was found. The substitution of proline for Trp-33 (in the region of the first alpha helix) showed no activity, while four additional substitutions (lysine, leucine, cysteine, and glutamic acid) showed low activity. Altered sugar specificity was observed when Trp-33 was replaced by serine, glutamine, tyrosine, alanine, histidine, or phenylalanine. It is concluded that Trp-33 may be involved directly or indirectly in sugar recognition. 相似文献
997.
998.
999.
Peng Xue Tao Jiang Juan Zhu Meixian Wang Qiaoling Zhao Jinshan Huang Shunming Tang Xingjia Shen 《Journal of Asia》2021,24(1):42-49
N6-methyladeosine (m6A) plays an important role in virus infection and replication. Bombyx mori nuclear polyhedrosis is caused by Bombyx mori nucleopolyhedrovirus (BmNPV) infection. Expression levels of m6A-modification-related genes after the infection of BmNPV were detected at first. Then, expression levels of BmNPV nucleocapsid protein gene VP39 and envelope fusion protein gene GP64 after knockdown of METTL3in vitro were quantified to identify the effect of m6A modification on BmNPV. BmNPV firstly infects the larval midgut in case of oral infection. Subsequently, to clarify the relationship between m6A modification and resistance of the silkworm to BmNPV, we detected the expression levels of m6A-modification-related genes invivo before and after infection of BmNPV. The results indicated that low METTL3 level hindered the proliferation of BmNPV to some extent, and silkworm strain with low METTL3 level showed stronger resistance against BmNPV. This study will accumulate new experimental data for elucidating the resistance mechanism of silkworm against BmNPV. 相似文献
1000.