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树干毕赤酵母(Pichia Stipitis)木糖还原酶(xyl1)基因克隆与序列分析 总被引:1,自引:0,他引:1
根据木糖还原酶基因序列相似的特点,设计一对引物获得Pichia stipitis CICC1960的一段基因片段,此片段长度为957bp,共编码318个氨基酸.利用生物信息学软件对该序列进行了同源性分析、氨基酸组成分析、疏水性分析、磷酸化位点预测、CDS 分析及二、三级结构预测.结果表明该片段为Pichia stipitis CICC1960木糖还原酶基因序列. 相似文献
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用可逆非竞争性抑制的动力学方程分析3-硝基-N-甲基水杨酰胺对琥珀酸细胞色素c还原酶的抑制作用,发现在高浓度抑制剂条件下实验数据偏离动力学方程。以大豆磷脂取代酶中的天然磷脂后,不再出现这种偏离。这一现象可能与呼吸链酶的双体特征有关。 相似文献
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还原六价铬细菌及其还原酶的研究 总被引:1,自引:0,他引:1
从活性污泥中筛选出的C-2苏云金芽孢杆菌,能耐受250mg/L的六价铬,并具有较好的还原能力。研究表明木糖、果糖、玉米饼粉、苹果酸、琥珀酸、柠檬酸及Cu2+、Fe2+、Ca2+离子对C-2菌的还原有积极作用,菌体的接种量影响还原的速率。C-2菌还原的最适温度为37℃,最适pH为9.0;六价铬还原酶的最适pH为7.0、温度为37℃,Co2+、Cu2+、Fe2+、DTT、NADH对酶的还原有积极影响。 相似文献
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3-硝基-N-甲基水杨酰胺对琥珀酸细胞色素c还原酶的抑制作用 总被引:1,自引:0,他引:1
我们发现3-硝基-N-甲基水杨酰胺对猪心线粒体呼吸链的琥珀酸细胞色素c还原酶活力有抑制作用。抑制部位在呼吸链中PMS和DCPIP的电子给体之间。抑制性质表现为可逆非竞争性。 相似文献
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通过克隆分离鉴定得到大鼠硝基还原酶结构域蛋白1(rNOR1),发现rNOR1 cDNA含有1 418 个碱基,编码含379个氨基酸残基的rNOR1蛋白.rNOR1与人类NOR1 (hNOR1)和小鼠NOR1 (mNOR1)的同源性分别为89% 和93%,这三种同源蛋白都含有OSCP1家族的保守结构域.rNOR1基因在大鼠睾丸中选择性高表达,而且与之同源的人类hNOR1也选择性高表达于睾丸中.通过免疫组化检测人类不同睾丸癌中的hNOR1蛋白表达,发现hNOR1蛋白在非癌变睾丸组织和胚胎性癌组织中高表达,而在精原细胞癌和分化型非精原细胞癌(畸胎瘤,卵黄囊瘤)中低表达.这些数据表明,hNOR1可能是一种睾丸选择性表达基因,睾丸癌hNOR1表达的改变或许可以帮助我们阐明hNOR1蛋白在生殖细胞系肿瘤发生中的功能. 相似文献
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木糖还原酶(XR, EC 1.1.1.21)是真菌微生物代谢木糖的关键酶之一。本文以米曲霉基因组DNA为模板,克隆木糖还原酶基因(xr,GenBank登录号:FJ957890.1),并对XR的序列、系统进化树、理化性质及蛋白结构等进行生物信息学分析。结果表明: xr基因序列长1449 bp,其中开放阅读框长960 bp,编码319个氨基酸,蛋白质分子质量35.9 kDa,等电点为5.78;米曲霉XR与其他菌种XR有较高的同一性,含有醛酮还原酶家族的两个指纹结构和一个参与辅酶结合活性位点指纹结构,以及醛酮还原酶家族典型的(β/α)8 TIM桶结构,说明米曲霉XR属于醛酮还原酶家族。 相似文献
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Most nitroaromatic compounds are toxic and mutagenic for living organisms, but some microorganisms have developed oxidative or reductive pathways to degrade or transform these compounds. Reductive pathways are based either on the reduction of the aromatic ring by hydride additions or on the reduction of the nitro groups to hydroxylamino and/or amino derivatives. Bacterial nitroreductases are flavoenzymes that catalyze the NAD(P)H-dependent reduction of the nitro groups on nitroaromatic and nitroheterocyclic compounds. Nitroreductases have raised a great interest due to their potential applications in bioremediation, biocatalysis, and biomedicine, especially in prodrug activation for chemotherapeutic cancer treatments. Different bacterial nitroreductases have been purified and their biochemical and kinetic parameters have been determined. The crystal structure of some nitroreductases have also been solved. However, the physiological role(s) of these enzymes remains unclear. Nitroreductase genes are widely spread within bacterial genomes, but are also found in archaea and some eukaryotic species. Although studies on regulation of nitroreductase gene expression are scarce, it seems that nitroreductase genes may be controlled by the MarRA and SoxRS regulatory systems that are involved in responses to several antibiotics and environmental chemical hazards and to specific oxidative stress conditions. This review covers the microbial distribution, types, biochemical properties, structure and regulation of the bacterial nitroreductases. The possible physiological functions and the biotechnological applications of these enzymes are also discussed. 相似文献
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双酚类化合物(bisphenols,BPs)作为工业原料及药物和个人护理品的重要成分之一,在自然界中广泛分布。BPs作为类雌性激素造成的生态风险已成为全球备受关注的环境问题之一。研究人员使用不同方式分离得到菌株或菌群,尝试对BPs进行无害化降解,目前已取得了一些重要的研究进展。本文对近年来细菌降解BPs的相关研究进行了系统梳理,重点关注以双酚A(bisphenol A,BPA)为典型BPs的细菌降解,总结不同路径中的关键作用基因,讨论相同路径中酶的差异及作用方式,并分析其对BPA的降解效果。本文也简要总结了双酚S(bisphenolS,BPS)和其他BPs的细菌降解研究情况。通过总结讨论现有成果,分析细菌降解BPs中尚需深入研究的内容,探寻未来BPs细菌降解机理及应用的研究方向。 相似文献
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Lycklama A Nijeholt JA Driessen AJ 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2012,367(1592):1016-1028
Most bacterial secretory proteins pass across the cytoplasmic membrane via the translocase, which consists of a protein-conducting channel SecYEG and an ATP-dependent motor protein SecA. The ancillary SecDF membrane protein complex promotes the final stages of translocation. Recent years have seen a major advance in our understanding of the structural and biochemical basis of protein translocation, and this has led to a detailed model of the translocation mechanism. 相似文献
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Dynein is a minus-end-directed microtubule motor crucial to diverse cellular processes. The unwieldy size of the molecule and the difficulty of expressing and purifying mutants have hampered mechanistic studies of dynein. Recent progress sheds light on key unsolved questions concerning how the molecule is really organized, what conformational changes accompany ATP hydrolysis and whether two or three motor domains are coordinated in their motion. 相似文献
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