Ribosome Inactivating Proteins from Plants Inhibiting Viruses

Many plants contain ribosome inactivating proteins (RIPs) with N-glycosidase activity, which depurinate large ribosomal RNA and arrest protein synthesis. RIPs so far tested inhibit replication of mRNA as well as DNA viruses and these proteins, isolated from plants, are found to be effective against a broad range of viruses such as human immunodeficiency virus (HIV), hepatitis B virus (HBV) and herpes simplex virus (HSV). Most of the research work related to RIPs has been focused on antiviral activity against HIV; however, the exact mechanism of antiviral activity is still not clear. The mechanism of antiviral activity was thought to follow inactivation of the host cell ribosome, leading to inhibition of viral protein translation and host cell death. Enzymatic activity of RIPs is not limited to depurination of the large rRNA, in addition they can depurinate viral DNA as well as RNA. Recently, Phase I/II clinical trials have demonstrated the potential use of RIPs for treating patients with HIV disease. The aim of this review is to focus on various RIPs from plants associated with anti-HIV activity.

Anti-tumor activities and apoptotic mechanism of ribosome-inactivating proteins

Ribosome-inactivating proteins(RIPs) belong to a family of enzymes that attack eukaryotic ribosomes and potently inhibit cellular protein synthesis.RIPs possess several biomedical properties,including anti-viral and anti-tumor activities.Multiple RIPs are known to inhibit tumor cell proliferation through inducing apoptosis in a variety of cancers,such as breast cancer,leukemia/lymphoma,and hepatoma.This review focuses on the anti-tumor activities of RIPs and their apoptotic effects through three closely related pathways:mitochondrial,death receptor,and endoplasmic reticulum pathways.

Isolation of a genomic DNA for Jatropha curcas ribosome inactivating protein and its tobacco transformation

Genomic DNA for Jatropha curcas ribosome inactivating protein （JRIP） was cloned from total DNA of its leaves by polymerase chain reaction （PCR）. The no intron character was confirmed. The plant expression vector pBI121-JRIP was constructed by inserting the JRIP gene into pBI121 plasmid. The recombinant Agrobacterium EHA105 strain harboring pBI121-JRIP was constructed by conducting pBI121-JRIP to strain EHA 105. PCR and Southern blotting were carried out, and the results proved that the JRIP gene was integrated into tobacco genome. It might provide a new material for disease resistance tobacco species breeding.

Crystallization and Preliminary Crystallographic Studies of Cucurmosin 2,a Ribosome-inactivating Protein from the Sarcocarp of Cucurbita moschata

Cucurmosin 2, a type 1 ribosome-inactivating protein （RIP） isolated from sarcocarp of Cucurbita moschata, has been crystallized by the vapor-diffusion method using PEG6000 as the precipitant. The crystals belong to the orthorhombic space group P212121, with unit cell parameters a = 55.853, b = 65.507, c = 91.754 А, and have one molecule per asymmetric unit. X-ray data have been collected to 1.8А, using a synchrotron source.

Crystallization and Preliminary Crystallographic Studies of Luffaculin 1,a Ribosome-inactivating Protein from the Seeds of Luffa Acutangula

Luffaculin 1 purified from the seeds of Luffa acutangula belongs to the type I ribosome-inactivating proteins （RIPs）. It has been crystallized by the vapor-diffusion method using polyethylene glycol as a precipitant. The crystal is of space group P1 with a = 39.135, b = 46.813, c = 83.571 A, α = 891068,β = 80.009 and y = 72.143°, and has two molecules per asymmetric unit. X-ray data have been collected to be 1.4 A using a synchrotron source.

苦瓜籽RIP的分离纯化及其对K562细胞作用的研究

目的:采用强阳离子交换层析柱(SP Sepharose H igh Perform ance)分离纯化苦瓜籽R IP,并观察苦瓜R IP对人红白血病细胞株K562细胞的抗肿瘤活性。方法:采用强阳离子交换层析柱(SP Sepharose H igh Perform-ance)分离纯化苦瓜籽R IP,SDS-PAGE、IEF等实验鉴定苦瓜籽R IP的纯度;以一定浓度梯度的苦瓜籽R IP处理K562细胞72 h,CCK-8检测其对细胞生长的影响;流式细细术(AnnexinⅤ)、细胞形态学(光镜及电镜)等方法检测苦瓜R IP诱导K562细胞凋亡的产生。结果:应用强阳离子交换层析柱(SP Sepharose H igh Perform ance)来分离纯化苦瓜籽R IP,可以快速方便分离得到高纯度的苦瓜R IP,得率也较高;一定作用剂量的苦瓜R IP不仅具有抑制K562细胞生长的活性(9.1μg/mL)的作用,还可诱导K562细胞发生凋亡。结论:运用强阳离子交换层析柱(SPSepharose H igh Perform ance)分离纯化苦瓜R IP是便捷可行的;苦瓜R IP具有抗肿瘤的活性,其作用可能是通过诱导细胞发生凋亡来实现。

茶树Ⅱ型核糖体失活蛋白基因CsRIP1和CsRIP2的克隆与表达分析

【目的】克隆茶树Ⅱ型核糖体失活蛋白基因CsRIP1和CsRIP2,探讨CsRIPs基因的组织表达特异性以及假眼小绿叶蝉和机械伤害处理对其表达的影响。【方法】Cs-Ev2(Gen Bank登录号:GH618807)为一受假眼小绿叶蝉取食诱导的茶树Ⅱ型核糖体失活蛋白基因的c DNA片段,利用RACE技术克隆该基因的全长c DNA,命名为CsRIP1(Gen Bank登录号:FJ648831)。利用RT-PCR技术从茶树子叶中分离出一个新的Ⅱ型核糖体失活蛋白基因的c DNA序列,命名为CsRIP2(Gen Bank登录号:GU951535)。利用PCR技术克隆CsRIPs的基因组序列。设计基因特异性引物,利用Real-time qRT-PCR技术检测CsRIPs的组织表达特异性,以及在叶片中假眼小绿叶蝉和机械伤害处理对其表达的影响。【结果】CsRIP1和CsRIP2的序列一致性为98%,都含有一个1 713 bp的开放阅读框,编码570个氨基酸残基,但是它们具有不同的3'非翻译区。CsRIP1和CsRIP2由信号肽序列、1个RIP结构域、链接肽和2个RBL结构域组成。CsRIPs与其他Ⅱ型RIPs具有较高的序列一致性,Ⅱ型RIPs保守的氨基酸残基,包括构成A链N-糖苷酶活性位点的氨基酸残基、B链中形成寡糖链结合位点的氨基酸残基、形成链间和链内二硫键的半胱氨酸残基以及RBL结构域中的Qx W基序,均出现在CsRIPs相应的位置上。系统进化树分析结果显示,同一物种的Ⅱ型RIPs首先聚类合并,2个CsRIP与樟的Ⅱ型RIPs聚为一支。比较CsRIPs的c DNA序列和基因组序列,发现它们的基因组序列不含内含子。CsRIPs基因的表达具有组织特异性,CsRIP1在叶片中的表达水平最高,在子叶中的表达水平最低,而CsRIP2在子叶中的表达水平最高,在叶片中的表达水平最低。在叶片中,CsRIP1和CsRIP2的表达均受假眼小绿叶蝉取食的强烈诱导,并且其表达水平随着取食时间的增加而逐渐增加,取食48 h后,它们的表达水平大约分别是对照的120和100倍。在叶片中,CsRIPs基因的表达也受机械伤害处理的诱导,CsRIP1的转录水平在处理后6 h达到最大值,CsRIP2在处理后6 h表达水平显著升高,12 h达到最大值。【结论】克隆茶树的2个Ⅱ型核糖体失活蛋白基因,它们可能参与茶树的防卫反应,且已发生亚功能化。进一步分析这2个基因的启动子,可以加深对CsRIPs基因转录调控以及RIPs的生物学功能的理解。

麻疯树核糖体失活蛋白Curcin和Curcin C的RNA N-糖苷酶活性研究

为探究麻疯树核糖体失活蛋白的RNA N-糖苷酶活性,本研究建立了UPLC-MS/MS方法测定麻疯树核糖体失活蛋白Curcin、Curcin C的体外RNA N-糖苷酶脱嘌呤活性.通过单因素实验得到Curcin与RNA32脱嘌呤反应时,反应的最适条件为37℃、pH=4.2、反应时间为4 h.当Curcin C与RNA32脱嘌呤反应时,反应的最适条件为37℃、pH=3.7、反应时间为8 h.Curcin的K_(m)值为8.231μmol/L,Curcin C的K_(m)值为3.302μmol/L,说明Curcin C与底物的亲和力更大.部分金属离子对CurcinC的酶活性具有促进作用,而对Curcin而言均产生了抑制.腺苷浓度达到250μmol/L时,Curcin C酶活性升高,而对于Curcin没有影响.当酶促反应底物为RNA14和RNA32时,Curcin C蛋白的RNA N-糖苷酶活性都显著高于Curcin,表明Curcin C相较于Curcin更具有抗肿瘤药物开发潜力.

Ⅰ型核糖体失活蛋白(RIPs)抗肿瘤作用的研究进展

目的介绍Ⅰ型核糖体失活蛋白抗肿瘤作用的研究概况及展望。方法总结核糖体失活蛋白抗肿瘤作用及机制。结果Ⅰ型核糖体失活蛋白具有明显的抗肿瘤作用。结论Ⅰ型核糖体失活蛋白是很有发展前景的抗肿瘤植物药。

绞股蓝RIP基因双子叶植物表达载体的构建及其对烟草叶盘的转化

将绞股蓝(Gynostemmapentaphyllum)核糖体失活蛋白(Ribosome-InactivatingProtein,RIP)cDNA序列(Gen Bank登录号AY279219)插入到pKYLX71∶35S2植物表达载体的HindIII/SacI位点处,构建了适于在双子叶植物中表达的载体,并经三亲交配法转入土壤农杆菌LBA4404,用于转化烟草品种K-326,分子鉴定表明绞股蓝RIP基因已经整合到再生烟苗的基因组中并发生了转录。

Purification and Characterization of a New Ribosome Inactivating Protein from Cinchonaglycoside C-treated Tobacco Leaves

A new ribosome-inactivating protein （RIP） with a molecular weight of 31 kDa induced by Cinchonaglycoside C （1） designated CIP31, was isolated from tobacco leaves. Analysis of this protein sequence indicated that it belongs to the RIP family and it was distinct from the other plant RIPs reported previously at its N-terminal amino acid sequence. CIP31 can directly impair synthesis of coat protein （CP） of tobacco mosaic virus （TMV）, which resulted in inhibition of TMV long distance movement and multiplication in tobacco plants at concentrations of ng/mL. Furthermore, no toxicity was shown to the growth and fertility of the plants. CIP31 was synthesized only in the presence of Cinchonaglycoside C （1） and was independent of the salicylic acid （SA） signal pathway. We provided evidence for the SA-independent biological induction of resistance.

Trichobitacin-a new ribosome-inactivating protein Ⅰ.The isolation,physicochemical and biological properties of trichobitacin

From the press-residue of the fresh root tuber of Trichosanthes kirilowii Maxim (Cu-curbitaceae),a new ribosome-inactivating protein (RIP),trichobitacin,was isolated.It has the activity of RNA N-glycosidase and can inhibit the growth of human placental trophoblastic cells.Its molecular weight is 27,228 Da (ES-MS) and pI 9.6.It is a single chain basic RIP.Its amino acid composition was determined.It is a new RIP.It consists of 0.7~0.9% galactose and may be a glycoprotein.Its A'-and C-terminal amino acid is Asp and Ala,respectively.Its N-terminal preliminary amino acid sequence has been determined.

Visualization of interaction between ribosome-inactivating proteins and supercoiled DNA with an atomic force microscope

The interaction between ribosome-inactivating proteins (RIPs) and supercoiled DNA was observed with an atomic force microscope (AFM). It was found that RIPs can bind to both supercoiled DNA and the unwound double stranded loop region in supercoiled DNA. The RIPs hound to the supercoils can induce the conformational change of supercoiled DNA. Furthermore, the supercoiled DNA was relaxed and cleaved into nick or linear form by RIPs. It indicated that RIP seemed to be a supercoil-dependent DNA binding protein and exhibited the activity of su-percoil-dependent DNA endonuclease.

Primary structure of p-momorcharin, a ribosome-inactivating protein from the seeds of Momordica Charantia Linn (Cucurbitaceae)

The complete amino acid sequence of β-momorcharin, a ribosome-inactivating protein from the seeds of Momordica charantia Linn (Cucurbitaceae) has been determined. This has been done by the sequence analysis of peptides obtained by enzymatic digestion with trypsin, chymotrypsin and S. aureus V8 protease, as well as by chemical cleavage with BNPS-skatole. The protein consists of 249 amino acid residues containing one asparagine - linked sugar group attached to the site of Asn 5 1 and has a calculated relative molecular mass of 28,452 Da without addition of the carbohydrate. Comparison of this sequence with those of trichosanthin and other ribosome-inactivating proteins from different species of plants shows a significant homology with each other. Regarding the similarity of their biological properties, an active domain of these proteins has been predicted here.

苦瓜核糖体失活蛋白的纯化及其诱导HL-60细胞凋亡的研究

目的: 探讨运用假配基亲和层析和凝胶过滤层析相结合的手段纯化苦瓜核糖体失活蛋白(RIP)的可行性,同时观察其抑制HL-60细胞增殖并诱导其发生凋亡的生物学活性。方法: 利用假配基亲和层析法、凝胶过滤层析法提取纯化苦瓜RIP;通过绘制生长曲线和MTT检测观察苦瓜RIP抑制HL-60细胞增殖的活性,运用流式细胞仪检测细胞周期相分布及细胞凋亡率。结果: 运用硫酸铵分级沉淀、Blue Sepharose CL-6B假配基亲和层析、Sephadex-G75凝胶层析等方法提取、纯化得到了高纯度的苦瓜RIP,并且能够获得较高的得率;一定作用剂量的苦瓜RIP不仅能够抑制HL-60细胞的增殖活性,还可以诱导其发生凋亡。结论: 运用假配基亲和层析和凝胶过滤层析相结合的手段提取、纯化苦瓜RIP是可行的;苦瓜RIP可能是通过诱导细胞发生凋亡来发挥其抗肿瘤活性。

苦瓜子蛋白的分离纯化及其性质研究

从苦瓜种子的粗提物苦瓜子蛋白丙酮分级沉淀干粉中,用CM-Sephadex C-50和SephadexG-75分离得到了两个核糖体失活蛋白,α-苦瓜子蛋白(α-momorcharin,α-MMC)和β-苦瓜子蛋白(β-momorcharin,β-MMC),其等电点分别为9.10(α-MMC),9.32(β-MMC).用ESI-MS和MALDI-TOF-MS测定它们的分子量,分别为28625(α-MMC),29076(β-MMC)(+Na,29099);,28795(α-MMC),29074.7(β-MMC).它们都是糖蛋白.其生物活性的分析测定表明,都属于RNA N-糖苷酶.本文重点对β-苦瓜子蛋白的分离纯化及其性质进行详细报道,并对其N-端部分的氨基酸顺序进行了测定.

麻疯树(Jatropha curcas)毒蛋白curcin基因家族成员的分离和描述

麻疯树curcin基因家族中4个成员通过PCR扩增被分离.它们都不含有内含子,序列分析表明它们编码Ⅰ型核糖体失活蛋白(Ribosome-Inactivating Proteins,RIPs),证明curcin基因如同大多数RIPs一样由多基因家族编码.四个curcin基因家族成员和另两个已知curcin基因家族成员的开放阅读框(Open Reading Frame,ORF)的序列比对结果显示curcin基因家族成员至少可分为两个亚类群,亚类群之间的氨基酸序列相似性低于88%.分别将这4个curcin基因家族成员命名为curA2、curA3、curB2、curB3.对四条基因启动子区和ORF生物信息学分析推测curB2、curB3可能是被真菌及逆境诱导的curcin基因家族成员全长,而curA2、curA3可能是麻疯树胚乳贮存的curcin基因家族成员全长.Southern杂交结果显示,麻疯树基因组中至少有3个以上curcin基因家族成员.

植物类中药活性蛋白成分研究进展

从植物的蛋白质类成分中寻找新的药物是今后一个重要的发展方向。已有的研究表明 ,植物蛋白具有多方面的生物活性。核糖体失活蛋白是植物中广泛存在的一类具有较好抗肿瘤活性的蛋白质 ,通过干扰肿瘤细胞遗传信息链而诱导细胞凋亡 ;MAP30 ,PAP,GAP31等植物蛋白通过影响病毒 DNA复制表达而显示出抗 HIV病毒活性 ;多种植物蛋白还通过促进免疫细胞增殖、提高免疫细胞功能 ,起到增强免疫调节的作用。此外 ,在清除体内氧自由基、催化纤维蛋白原溶解等方面 ,植物蛋白也显示出明显的活性。

苦瓜籽核糖体失活蛋白的基本性质研究

采用 Affi- Gel亲和层析和 Sephacryl S- 10 0分子筛层析等方法获得苦瓜籽核糖体失活蛋白 (RIP) ,经 SDS- PAGE,PAGE,IEF和 PAS方法分析均表明为单一蛋白着色带或单一糖蛋白着色带 .根据 SDS- PAGE测得表观分子量为 30 0 0 0 ,经 IEF- PAGE结果计算其 PI为 9.0 ,对无细胞系统中蛋白质生物合成抑制活性明显 ,其 IC50 为 5.3× 10 -10 mol/ L左右 .体外生物活性试验结果表明其对人肝癌细胞 ,Vero,SP2 / 0 ,3T3,Kb,Navana,S- 180等肿瘤细胞株和麻疹病毒均表现有不同程度的抑制作用 ,而对完整人胚肺二倍体细胞却毒性极小 .

天花粉蛋白基因的克隆及序列分析

本文应用ＤＮＡ多聚酶链式反应（ＰＣＲ）技术，从栝楼基因组ＤＮＡ中扩增并克隆了天花粉蛋白（ＴＣＳ）基因。核酸序列分析结果表明，克隆片段包括ＴＣＳ的前原蛋白的编码序列和５＇一侧翼区段。其编码序列与已发表的不同来源的３种ＴＣＳ基因的核苷酸序列的同源性分别为９９．２０％，９８．７４％和９８．６４％。推导出的氨基酸序列与已发表的４种ＴＣＳ的氨基酸序列的同源性分别为９８．６２％、９８．６２％、９７．４１％和９８．３８％。另外还发现，我们克隆的ＴＣＳ基因的５＇一侧翼区段比已发表的ＴＣＳ基因的相应区段多一个类似于ＴＡＴＡ盒的序列。我们进一步构建了该基因的一系列突变体，为深入研究ＴＣＳ基因结构、表达和调节机制以及ＴＣＳ的结构和功能关系奠定了重要的基础。