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烟草花叶病毒衣壳蛋白(TMV-CP)的叶绿体离体跨膜运输特性及种属特异性 总被引：1，自引：0，他引：1
为探明烟草花叶病毒衣壳蛋白（TMV-CP）的叶绿体离体跨膜运输特性及种属特异性,研究了时间、TMV-CP浓度对跨膜运输的影响以及TMV-CP跨膜的种属选择性。结果表明,TMV-CP可以快速地进入离体烟草叶绿体中,超过15min的跨膜时间对进入叶绿体中CP的浓度没有影响;加入跨膜体系中的TMV-CP的浓度与跨膜后进入叶绿体的TMV-CP浓度呈正相关;TMV-CP的叶绿体离体跨膜运输具有种属选择性,推测这可能是TMV不能感染禾本科植物的原因。 相似文献
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腺苷三磷酸结合盒转运蛋白（ATP-binding cassette transporter,ABC转运蛋白）是一类大量存在于原核生物及真核生物的跨膜转运蛋白,其种类繁多、家族庞大且功能多样,主要功能是利用ATP水解产生的能量将底物进行逆浓度梯度跨膜运输,同时还参与抗原传递、信号传导和细胞解毒等很多重要的生物生理过程。综述了ABC转运蛋白的结构特点、跨膜吸收机制及影响因素,为研究ABC转运蛋白跨膜吸收转运养分离子及其抵抗非生物逆境胁迫提供理论支撑和研究思路。 相似文献
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【目的】明确离体条件下水稻条纹病毒（RSV）外壳蛋白（CP）能否进入叶绿体,为研究RSV的致病机理提供依据和方法。【方法】参考有关文献的方法提取获得水稻和小麦叶绿体,在离体条件下进行RSV-CP的叶绿体跨膜运输试验,同时研究孵育时间、病毒浓度等对RSV-CP在水稻叶绿体中离体跨膜运输的影响。【结果】在离体条件下5 min, RSV-CP即可进入RSV寄主植物水稻、小麦的叶绿体内,其离体跨膜运输的基本条件为RSV浓度58.1 μg/mL、孵育时间15 min。随着孵育时间的延长,进入叶绿体中的CP量有所增加;反应体系中RSV浓度加大,进入叶绿体中的RSV-CP量随之增加。【结论】离体条件下RSV-CP可进入寄主植物水稻、小麦的叶绿体中,病毒外壳蛋白进入叶绿体可能是其诱发花叶症状的主要原因之一。 相似文献
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[目的]明确离体条件下水稻条纹病毒(RSV)外壳蛋白(CP)能否进入叶绿体,为研究RSV的致病机理提供依据和方法.[方法]参考有关文献的方法提取获得水稻和小麦叶绿体,在离体条件下进行RSV-CP的叶绿体跨膜运输试验,同时研究孵育时间、病毒浓度等对RSV-CP在水稻叶绿体中离体跨膜运输的影响.[结果]在离体条件下5min,RSV-CP即可进入RSV寄主植物水稻、小麦的叶绿体内,其离体跨膜运输的基本条件为RSV浓度58.1 μg/mL、孵育时间15 min.随着孵育时间的延长,进入叶绿体中的CP量有所增加;反应体系中RSV浓度加大,进入叶绿体中的RSV-CP量随之增加.[结论]离体条件下RSV-CP可进入寄主植物水稻、小麦的叶绿体中,病毒外壳蛋白进入叶绿体可能是其诱发花叶症状的主要原因之一. 相似文献
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研究了重组脂蛋白体中K^ 运输蛋白对K^ 的转运特征。当外界pH值为7.5时，ATPase和K^ 转运的相对活力最高。加入10μmol/L钒酸钠，抑制50％ ATPase活力和K^ 转运，表明对钒酸钠敏感；同时，由该运输蛋白参与的K^ 跨膜运输受外界ATP和K^ 浓度影响，其Km值分别为60μmol/L和14μmol/L，表明专一性亲和ATP和K^ ，与膜两侧电势梯度无关。 相似文献
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ABC（ATP-binding cassette）转运蛋白家族庞大,种类繁多,包括全转运子和半转运子等2种类型。全转运子的核心单元包括2个核苷酸结构域（NBD）和2个跨膜结构域（TMD）,而半转运子只含有1个膜结构域（MSD）和1个NBD。植物ABC转运蛋白不仅参与植物体内激素、脂质、金属离子、次生代谢物和外源物质的运输,并且有利于植物与病原体间的相互作用和植物体内离子通道调控等重要的生理过程的进行,是一类重要的跨膜运输蛋白家族。HUGO系统中ABC家族分为A~H 8个亚族,模式植物基因组测序的完成极大促进了ABC转运蛋白的研究与发现,近几年已从多种植物中克隆了不同亚族的基因并研究其表达与功能,但目前的研究主要集中在ABCB,ABCC,ABCG等三大亚族。植物ABC转运蛋白各亚族的结构与功能截然不同,在不同植物中的表达部位也千差万别。综述了植物ABC转运蛋白家族的研究进展,根据ABC家族中已知的重要成员,系统阐述植物中各亚族ABC转运蛋白的结构特征、在植物中的表达及其生物学功能,并为今后可能的研究提出展望。表1参49 相似文献
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奶牛乳脂中的长链脂肪酸（LCFA）JL乎全部来源于从消化道吸收并转运人血液的食物外源性LCFA,然后跨膜进入乳腺上皮细胞参与乳脂合成,而参与LCFA跨膜运输的脂肪酸转运蛋白有：脂肪酸转运蛋白家族（Fattyacid transport proteins,FAPTs）、脂肪酸转位酶（Fatty acid translocase,FAT／CD36）、脂肪酸结合蛋白家族（Fattyacid binding proteins,FABPs）和小窝蛋白（Caveolinproteins）。文章在综述LCFA跨膜运输研究的基础上,重点介绍4种LCFA转运蛋白的研究进展,发现在奶牛乳腺中表达的只有FAT／CD36和FABPs,而FATPs和小窝蛋白在奶牛乳腺中是否表达并参与LCFA的转运仍有待进一步研究确定。因此,应利用营养学、分子生物学和细胞生物学等方法,在体内和体外对FAT／CD36、FABPs、FATPs和小窝蛋白在泌乳期奶牛乳腺中的表达规律、作用机理进行深入研究,以探明其在乳腺LCFA转运中的作用及调控机制．并为优化乳脂组成实施的营养调控提供科学依据。 相似文献
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锌铁转运蛋白ZIP家族成员对于控制植物体内锌铁平衡具有非常重要的作用.采用生物信息的方法对植物锌铁转运蛋白序列结构、性质及分子进化进行分析预测,结果发现,该蛋白由226～459个氨基酸组成,是一个多次跨膜蛋白,多数成员定位于细胞质膜、叶绿体膜及液泡膜上,其分子进化历程与物种进化历程并不一致,提示该蛋白序列分歧时间较早.研究结果能够为该蛋白基因的克隆、结构和功能的进一步深入研究提供理论基础. 相似文献
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幼叶黄化油菜突变体Cr3529中Toc33 cDNA的克隆和序列分析 总被引：4，自引：0，他引：4
分别提取甘蓝型油菜幼叶黄化突变体Cr3529和野生型近等基因系3529幼叶期总RNA,反转录合成cDNA,根据拟南芥Toc33基因的编码区序列设计引物,RT-PCR扩增出叶绿体外膜转运机器构件蛋白基因Toc33。扩增产物与T载体连接,转化E.coli。获得cDNA克隆,分别命名为BnToc33-c和BnToc33,长度均为894 bp,与拟南芥Toc33cDNA有着较高的同源性。突变油菜Cr3529与野生型3529在Toc33的基因序列上有3处碱基存在差异,均为错义突变,其中一处位于TOC33蛋白的跨膜区域 相似文献
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After transport across the cytoplasmic membrane, bacterial outer membrane proteins are assembled into the outer membrane. Meningococcal Omp85 is a highly conserved protein in Gram-negative bacteria, and its homolog Toc75 is a component of the chloroplast protein-import machinery. Omp85 appeared to be essential for viability, and unassembled forms of various outer membrane proteins accumulated upon Omp85 depletion. Immunofluorescence microscopy revealed decreased surface exposure of outer membrane proteins, which was particularly apparent at the cell-division planes. Thus, Omp85 is likely to play a role in outer membrane protein assembly. 相似文献
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In Gram-negative bacteria, the import of essential micronutrients across the outer membrane requires a transporter, an electrochemical gradient of protons across the inner membrane, and an inner membrane protein complex (ExbB, ExbD, TonB) that couples the proton-motive force to the outer membrane transporter. The inner membrane protein TonB binds directly to a conserved region, called the Ton-box, of the transporter. We solved the structure of the cobalamin transporter BtuB in complex with the C-terminal domain of TonB. In contrast to its conformations in the absence of TonB, the Ton-box forms a beta strand that is recruited to the existing beta sheet of TonB, which is consistent with a mechanical pulling model of transport. 相似文献
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Protein targeting in eukaryotic cells is determined by several topogenic signals. Among these are stop-transfer regions, which halt translocation of proteins across the endoplasmic reticulum membrane. Two different stop-transfer regions were incorporated into precursors for a chloroplast protein, the small subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase. Both chimeric proteins were imported into chloroplasts and did not accumulate in the envelope membranes. Thus, the stop-transfer signals did not function during chloroplast protein import. These observations support the hypothesis that the mechanism for translocation of proteins across the chloroplast envelope is significantly different from that for translocation across the endoplasmic reticulum membrane. 相似文献
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《农业科学学报》2016,(5)
The nuclear-encoded light-harvesting chlorophyll a/b-binding proteins(LHCPs) are specifically translocated from the stroma into the thylakoid membrane through the chloroplast signal recognition particle(cp SRP) pathway. The cp SRP is composed of a cp SRP43 protein and a cp SRP54 protein, and it forms a soluble transit complex with LHCP in the chloroplast stroma. Here, we identified the YGL9 gene that is predicted to encode the probable rice cp SRP43 protein from a rice yellow-green leaf mutant. A phylogenetic tree showed that an important conserved protein family, cp SRP43, is present in almost all green photosynthetic organisms such as higher plants and green algae. Sequence analysis showed that YGL9 comprises a chloroplast transit peptide, three chromodomains and four ankyrin repeats, and the chromodomains and ankyrin repeats are probably involved in protein-protein interactions. Subcellular localization showed that YGL9 is localized in the chloroplast. Expression pattern analysis indicated that YGL9 is mainly expressed in green leaf sheaths and leaves. Quantitative real-time PCR analysis showed that the expression levels of genes associated with pigment metabolism, chloroplast development and photosynthesis were distinctly affected in the ygl9 mutant. These results indicated that YGL9 is possibly involved in pigment metabolism, chloroplast development and photosynthesis in rice. 相似文献
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Stengel KF Holdermann I Cain P Robinson C Wild K Sinning I 《Science (New York, N.Y.)》2008,321(5886):253-256
Secretory and membrane proteins carry amino-terminal signal sequences that, in cotranslational targeting, are recognized by the signal recognition particle protein SRP54 without sequence specificity. The most abundant membrane proteins on Earth are the light-harvesting chlorophyll a/b binding proteins (LHCPs). They are synthesized in the cytoplasm, imported into the chloroplast, and posttranslationally targeted to the thylakoid membrane by cpSRP, a heterodimer formed by cpSRP54 and cpSRP43. We present the 1.5 angstrom crystal structure of cpSRP43 characterized by a unique arrangement of chromodomains and ankyrin repeats. The overall shape and charge distribution of cpSRP43 resembles the SRP RNA, which is absent in chloroplasts. The complex with the internal signal sequence of LHCPs reveals that cpSRP43 specifically recognizes a DPLG peptide motif. We describe how cpSPR43 adapts the universally conserved SRP system to posttranslational targeting and insertion of the LHCP family of membrane proteins. 相似文献
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为研究低温下番茄细胞超微结构的变化,以耐寒性较弱的番茄品种010为试材,观察其幼苗经6、10、25℃处理后10d细胞超微结构的变化。结果表明:25℃处理下,叶绿体结构致密有序,体内类囊体片层有规则的整齐排列,细胞的超微结构中无嗜锇颗粒的积累;6、10℃低温处理下,叶绿体超微结构损伤,叶绿体部分膜解体破裂,类囊体片层结构排列紊乱,变形或扭曲,细胞内有较大的淀粉粒和大量嗜锇颗粒的积累。低温逆境导致番茄细胞膜系统和细胞结构受到破坏。 相似文献