共查询到19条相似文献,搜索用时 78 毫秒
1.
目的:心肌上的离子通道蛋白与心肌损伤有很大的关系,本研究通过低硒喂养对C57BL/6小鼠心肌组织损伤的影响及其对钾通道蛋白的改变。方法:将实验小鼠分为4组:对照组,低硒30天组,低硒90天组和低硒180天组。采用低硒饲料(硒含量0.0045μg/g)喂养的方法建立低硒小鼠模型,对照组给予正常饲料(硒含量0.256μg/g),与低硒组同时喂养;硒含量的测定和HE染色方法观察心肌损伤情况,Western Blotting方法检测其钾通道蛋白的表达。结果:低硒饲料喂养小鼠的心脏硒含量与正常饲料喂养的硒含量相比明显降低(P0.01);并出现轻微的心肌损伤,钾通道蛋白的表达量在低硒30天组,低硒90天组和低硒180天组下调(P0.01)。结论:成功建立低硒小鼠模型,低硒能引起小鼠心肌损伤,这种改变可能有心脏的钾通道蛋白的表达水平有关。 相似文献
2.
李新华 《国外医学:分子生物学分册》1998,20(4):188-191
心肌内向整流钾电流对维持静息电位和心肌的兴奋性有重要作用,1993年以来,多种内向整流钾通道(Kir)克隆成功,为探明通道的结构特性和内向整流的产生机理创造了条件,Kir肽链含两个跨膜段(M1,M2)4条肽链聚合成一个功能单位,内向整流是胞内Mg^2+和多聚胺与通道负电荷区域相互作用的结果,此区域可能与M2和C末端有关,这些进展为探讨通道的功能调节和新药设计提出了新的思路。 相似文献
3.
心肌钠,钾离子通道的分子生物学进展 总被引:1,自引:0,他引:1
分子生物学和电生理学(膜片钳技术)的联合应用研究对于阐明心肌钠、钾离子通道的分子结构与功能表达已取得突破性进展。现已证明,心肌钠离子通道主要由基β-亚单位作为功能性单位以表达出钠通道竭尽成分,其α-亚单位的存在可能改变钠电流的动力学性质。多种钾离子通道及其电流成分亦已在心肌细胞上鉴定出来。分子生物学研究已揭示出与心肌钠、钾通道功能表达有关的基因结构。在生理(例如心肌发生学过程中)情况下或病变心肌时 相似文献
4.
植物硒及其含硒蛋白的研究 总被引:5,自引:0,他引:5
硒是植物的有益元素,植物对硒的吸收与外源硒的有效性、硒的形态、植物的种类等有关;硒在植物中主要以有机硒形态存在,HPLC-ICP-MS联用已成为植物体内硒形态鉴定的最常用手段;含硒蛋白是植物体内最主要的有机大分子硒,具有抗肿瘤、抗氧化等多种生物活性。在环境安全和人类健康等方面,富硒植物具有很好的应用价值,所以利用分子生物学手段分析富硒植物的富硒机制,可以为富硒基因的筛选和利用提供理论依据。 相似文献
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6.
硒蛋白的生物合成与调控 总被引:4,自引:0,他引:4
硒蛋白是硒以硒半胱氨酸(Sec)形式参入形成的蛋白质。Sec作为参入蛋白质的第21种氨基酸,由硒蛋白mRNA上的UGA编码。在原核生物中,Sec参入硒蛋白的相关因子及其参入机制已基本阐明,Sec在SELA、SELB、SELC、SELD及Sec插入序列(SECIS)等的共同作用下参入到蛋白质中。在真核生物中,Sec参入硒蛋白的可能途径是:Ser-tRNA‘^[Ser]Sec。通过磷酸丝氨酰-tRNA^[Ser]Sec。最终转变为Sec-tRNA^[Ser]Sec,并在延伸因子及相关蛋白质因子的作用下参入到硒蛋白中。硒蛋白的合成在翻译前水平、mRNA水平、供硒水平等都受到相应的调控。 相似文献
7.
硒蛋白P的研究进展 总被引:1,自引:0,他引:1
硒蛋白P(SeP)是从大鼠和人血浆中分离、纯化得到的一种糖蛋白 ,每个硒蛋白P多肽含有10个硒代半胱氨酸。硒蛋白P中的硒含量占大鼠和人血浆中硒含量的 5 0 %以上。在其mRNA开放阅读框架中克隆的cDNA的序列含有 10个UGA密码子。硒代半胱氨酸在一个UGA密码子处嵌入蛋白的一级结构 ,尽管对硒蛋白P功能还没有彻底了解 ,它的一种非常可能的作用是作为一种胞外抗氧化剂。大鼠血浆中的硒蛋白P在体内实验中对Diquat诱导的脂质过氧化和肝损坏具有保护作用 ,人血浆中的硒蛋白P在体外实验中显示减少内毒素过氧化硝酸盐和磷脂氢过氧化物的活性。牛血浆中的硒蛋白P在神经细胞的培养中作为一存活促进因子。 相似文献
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生物合成硒蛋白机制的研究进展 总被引:8,自引:0,他引:8
作为第 2 1种氨基酸 ,硒代半胱氨酸在翻译阶段由核糖体介导 ,在mRNA编码区的UGA密码子处参入多肽链。研究表明硒代半胱氨酸的参入需要一个顺式作用元件SECIS和 4个基因产物 :SelA、SelB、SelC、SelD。原核生物和真核生物的SECIS在mRNA中的位置和结构特征差异显著。在利用Escherichiacoli硒代半胱氨酸的参入机制合成硒蛋白方面 ,研究人员进行了有益的探索。 相似文献
10.
硒蛋白P的研究进展 总被引:3,自引:0,他引:3
微量元素硒 (Se)作为许多具有重要生物功能的硒酶的活性中心 ,不但与机体的免疫应答及抗氧化作用等生理功能密切相关 ,而且能够降低癌症的发生率[1,2 ] 。在流行病学和临床研究中 ,常用血浆或全血中Se浓度作为衡量Se状态的指标 ,而且血浆浓度能比全血浓度更迅速地反映Se状态的变化。在哺乳动物血浆中 ,Se主要结合在 3种蛋白质中 :硒蛋白P、胞外谷胱甘肽过氧化物酶和清蛋白。其中硒蛋白P所含Se大约占血浆中全部Se浓度的 5 0 %。硒蛋白P不同于目前所鉴定的所有其他硒蛋白 ,因为它含有 10~ 12个硒代半胱氨酸 (SeCys)残… 相似文献
11.
目的探讨膜片钳实验中豚鼠、大鼠心肌细胞急性分离过程中的观察指标和影响因素,并进行膜片钳记录。方法使用改进的Langendorff恒流灌注法分离心肌细胞和全细胞膜片钳记录钾通道电流。结果分离即刻,存活细胞可达80%以上,复钙后约40%~50%呈静息状态,余出现自发性收缩,存活细胞能够进行膜片钳封接,于室温KB液中可成活8 h以上。结论使用恒流灌注法,观测灌注压的变化,可以较客观的掌握酶解消化的程度,利于获取生理状态良好的心肌细胞。且细胞能够进行膜片钳实验。 相似文献
12.
从分子水平上看,所有钾通道都是由一个基因家族中的基因所编码的4个亚基组成,通道的失活门控机制在N型、C型和P型三种,通道的孔道结构均在跨膜片段S5至S6之间,尽管各种钾通道在分子结构上的共处远多于不同之处,但每种钾通道的个性表现却有非常重要的生理意义,迄今为止在心肌细胞上发现的8种钾通道的电导值,门控动力学特征、离子动力学特征,通道激动剂,阻断剂和调制剂均不同。 相似文献
13.
The aim of this work was to investigate interactions of the human ether-a-go-go channel heag2 with human brain proteins. For this, we used heag2-GST fusion proteins in pull-down assays with brain proteins and mass spectrometry, as well as coimmunoprecipitation. We identified tubulin and heat shock 70 proteins as binding to intracellular C-terminal regions of the channel. To study functional effects, heag2 channels were expressed in Xenopus laevis oocytes for two-electrode voltage clamping. Coexpression of alpha-tubulin or the application of colchicine significantly prolonged channel activation times. Application at different times of colchicine gave similar results. The data suggest that colchicine application and tubulin expression do not affect heag2 trafficking and that tubulin may associate with the channel to cause functional effects. Coexpression of heat shock 70 proteins had no functional effect on the channel. The role of tubulin in the cell cytoskeleton suggests a link for the heag2 channel in tubulin-dependent physiological functions, such as cellular proliferation. 相似文献
14.
Regulation of the Kv2.1 Potassium Channel by MinK and MiRP1 总被引:1,自引:0,他引:1
Zoe A. McCrossan Torsten K. Roepke Anthony Lewis Gianina Panaghie Geoffrey W. Abbott 《The Journal of membrane biology》2009,228(1):1-14
Kv2.1 is a voltage-gated potassium (Kv) channel α-subunit expressed in mammalian heart and brain. MinK-related peptides (MiRPs),
encoded by KCNE genes, are single–transmembrane domain ancillary subunits that form complexes with Kv channel α-subunits to modify their
function. Mutations in human MinK (KCNE1) and MiRP1 (KCNE2) are associated with inherited and acquired forms of long QT syndrome
(LQTS). Here, coimmunoprecipitations from rat heart tissue suggested that both MinK and MiRP1 form native cardiac complexes
with Kv2.1. In whole-cell voltage-clamp studies of subunits expressed in CHO cells, rat MinK and MiRP1 reduced Kv2.1 current
density three- and twofold, respectively; slowed Kv2.1 activation (at +60 mV) two- and threefold, respectively; and slowed
Kv2.1 deactivation less than twofold. Human MinK slowed Kv2.1 activation 25%, while human MiRP1 slowed Kv2.1 activation and
deactivation twofold. Inherited mutations in human MinK and MiRP1, previously associated with LQTS, were also evaluated. D76N–MinK
and S74L–MinK reduced Kv2.1 current density (threefold and 40%, respectively) and slowed deactivation (60% and 80%, respectively).
Compared to wild-type human MiRP1–Kv2.1 complexes, channels formed with M54T– or I57T–MiRP1 showed greatly slowed activation
(tenfold and fivefold, respectively). The data broaden the potential roles of MinK and MiRP1 in cardiac physiology and support
the possibility that inherited mutations in either subunit could contribute to cardiac arrhythmia by multiple mechanisms.
Electronic supplementary material The online version of this article (doi: ) contains supplementary material, which is available to authorized users.
Z. A. McCrossan and T. K. Roepke have contributed equally to this work. 相似文献
15.
RT—PCR测定大鼠妊娠早期子宫孕激素受体基因的表达 总被引:4,自引:1,他引:3
孕激素在妊娠的建立和维持过程中起着非常重要的作用,但目前为止未见有关大鼠子宫 激素受体(PR)基因在该过程中表达情况的系统报道。本和反转偶联聚合酶链式反应(RT-PCR)方法测定了大鼠动情周期和妊娠早期子宫孕激素受体基因的转录,结果表明:1.动情周期中,子吕PRmRNA水平在动情期最高,在动情后期最低,动情期水平约为动情后期的2倍。2.妊娠开始后,子宫PRmRNA水平迅速上地d3-d4(着床前)达 相似文献
16.
Irina S. Dementieva Valentina Tereshko Zoe A. McCrossan Daniel Araki Nikolaus Grigorieff Steve A.N. Goldstein 《Journal of molecular biology》2009,387(1):175-976
We report the X-ray crystal structure of human potassium channel tetramerization domain-containing protein 5 (KCTD5), the first member of the family to be so characterized. Four findings were unexpected. First, the structure reveals assemblies of five subunits while tetramers were anticipated; pentameric stoichiometry is observed also in solution by scanning transmission electron microscopy mass analysis and analytical ultracentrifugation. Second, the same BTB (bric-a-brac, tramtrack, broad complex) domain surface mediates the assembly of five KCTD5 and four voltage-gated K + (Kv) channel subunits; four amino acid differences appear crucial. Third, KCTD5 complexes have well-defined N- and C-terminal modules separated by a flexible linker that swivels by ∼ 30o; the C-module shows a new fold and is required to bind Golgi reassembly stacking protein 55 with ∼ 1 μM affinity, as judged by surface plasmon resonance and ultracentrifugation. Fourth, despite the homology reflected in its name, KCTD5 does not impact the operation of Kv4.2, Kv3.4, Kv2.1, or Kv1.2 channels. 相似文献
17.
摘要目的:研究牛磺酸镁(TMCC)对哇巴因致豚鼠心肌细胞心律失常模型钙离子通道的作用机制。方法:运用全细胞膜片钳技术分别记录TMCC和胺碘酮对正常心肌细胞和哇巴因导致的心律失常心肌细胞模型钙离子通道的作用。结果:5bμmol/L哇巴因使心肌细胞钙离子通道电流(ICa-L)减小。200和400μmol/L可以明显使Ic}L恢复。24.26μmol/L胺碘酮使IM进一步减少(P〉0.05)。结论:400μmol/LTMCC可以明显加大正常细胞的b。,起到促进钙内流的作用,并且增强哇巴因致豚鼠心律失常心肌细胞异常减少的电流。 相似文献
18.
Tiago M. Pais Bertrand Garcia-Moreno Helena Santos 《Journal of molecular biology》2009,394(2):237-15164
Understanding protein stabilization by small organic compounds is a topic of great practical importance. The effect of mannosylglycerate, a charged compatible solute typical of thermophilic microorganisms, on a variant of staphylococcal nuclease was investigated using several NMR spectroscopy methods. No structural changes were apparent from the chemical shifts of amide protons. Measurements of 15N relaxation and model-free analysis, water-amide saturation transfer (phase-modulated CLEAN chemical exchange), and hydrogen/deuterium exchange rates provided a detailed picture of the effects of mannosylglycerate on the backbone dynamics and time-averaged structure of this protein. The widest movements of the protein backbone were significantly constrained in the presence of mannosylglycerate, as indicated by the average 5-fold decrease of the hydrogen/deuterium exchange rates, but the effect on the millisecond timescale was small. At high frequencies, internal motions of staphylococcal nuclease were progressively restricted with increasing concentrations of mannosylglycerate or reduced temperature, while the opposite effect was observed with urea (a destabilizing solute). The order parameters showed a strong correlation with the changes in the Tm values induced by different solutes, determined by differential scanning calorimetry. These data show that mannosylglycerate caused a generalised reduction of backbone motions and demonstrate a correlation between protein stabilization and protein rigidification. 相似文献
19.
植物钾营养高效与膜运系统的关系 总被引:1,自引:0,他引:1
HKT1和HAK1等转运子介导钾离子的高亲和吸收以及K^ /Na^ 共运转,从而可能增强Na^ 替代K^ 能力,KAT1和KST1等离子通道介导钾离子的累积和转运,从而调节气孔细胞的渗透压,控制气孔运动,阐述了植物生物膜上离子转运机制和钾营养高效机理的某种可能的关系,这些转运子和通道的高效表达可能与植物钾营养高效有很大的相关性。 相似文献