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厌氧微生物研究的新进展(续)凌代文(中国科学院微生物研究所,北京100080)rRNA/DNA和16SrRNA序列的测定已表明在系统发育上肠球菌和链球菌属、乳球菌属为同等相连群。当今使用反转录酶法分析测定16SrRNA全序列指示出肠球菌在系统发育上更... 相似文献
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以赤霉素(GA)处理后的G2豌豆为材料,构建了一个2.0×106的cDNA文库,用随机筛选法从该cDNA文库中得到一个完整的cDNA.其中1115bp全序列分析表明,它编码了豌豆5S核糖体RNA(5SribosomalRNA,5SrRNA),基因内部存在着与核糖体蛋白L5及5SrRNA结合蛋白(5SrRNABindingProtein)同源的区段,这些同源区段是蛋白与RNA结合的位点.基因内部还存在着大量的重复序列. 相似文献
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定向进化同源基因在细菌系统进化研究中的应用 总被引:12,自引:0,他引:12
1 细菌系统进化及分类研究的发展──从表型到基因型 近年来,随着分子生物学理论和技术的发展,细菌系统进化及分类研究有了长足的进步。过去,判断某一群细菌的分类地位,往往仅利用其表观特征,如细菌形态、菌落形态、生理特征、细胞组份等。随着分子生物学研究的深入,基因型特征成为细菌系统进化及分类研究的主要依据。常用的基因型特征包括:DNA G+Cmol%、DNA-DNA相关性分析、DNA指纹分析及rRNA同源性分析等。值得一提的是,Woese通过对各类生物rRNA序列进行分析,认为ssu rRNA(16S或… 相似文献
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由部分核糖体RNA序列研究的绿僵菌属种系统发育关系 总被引:5,自引:0,他引:5
本研究应用特异寡聚核酸引物和双脱氧核苷酸终止法测定绿僵菌Metarhizium不同种的部分rRNA序列。这些序列分别选自小亚基(18S)和大亚基(25S)rRNA上的不同区域。校排的不同序列用于计算核苷酸的差异。绿僵菌的系统发育关系采用最大可能性方法分析。所有的分类单元聚类成二个分支。在产生圆柱状瓶形小梗的种中,M.anisopliae var.anisopliae.M.anisopliae va 相似文献
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蓖麻蚕核糖体RNA基因(rDNA)5′-非转录间隔区有长约1kb的核骨架结合区SAR(scafold-associat-edregion)[1]。本文对该SAR元件的酵母自主复制功能进一步研究,证明该SAR5′端688bp含有12个ACS(ARS的核心序列)同源序列,但无ARS活性,而其3′端仅3个ACS同源序列,但对酵母的转化率比全片段还高40~50倍。体外结合实验证明,蓖麻蚕rRNA基因的SAR能专一地同酵母核骨架结合,提示ARS的功能体现与核骨架结合紧密相关。rRNA基因SAR与ARS的功能在进化上可能是很保守的。在此基础上可进一步分析SAR中与DNA复制相关的正调及负调元件。 相似文献
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Ribosomal protein S15 binds specifically to the central domain of 16 S ribosomal RNA (16 S rRNA) and directs the assembly of four additional proteins to this domain. The central domain of 16 S rRNA along with these five proteins form the platform of the 30 S subunit. Previously, directed hydroxyl radical probing from Fe(II)-S15 in small ribonucleoprotein complexes was used to study assembly of the central domain of 16 S rRNA. Here, this same approach was used to understand the 16 S rRNA environment of Fe(II)-S15 in 30 S subunits and to determine the ribosomal proteins that are involved in forming the mature S15-16 S rRNA environment. We have identified additional sites of Fe(II)-S15-directed cleavage in 30S subunits compared to the binary complex of Fe(II)-S15/16 S rRNA. Along with novel targets in the central domain, sites within the 5' and 3' minor domains are also cleaved. This suggests that during the course of 30S subunit assembly these elements are positioned in the vicinity of S15. Besides the previously determined role for S8, roles for S5, S6+S18, and S16 in altering the 16 S rRNA environment of S15 were established. These studies reveal that ribosomal proteins can alter the assembly of regions of the 30 S subunit from a considerable distance and influence the overall conformation of this ribonucleoprotein particle. 相似文献
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Characterization of Vibrio fischeri rRNA operons and subcloning of a ribosomal DNA promoter. 下载免费PDF全文
Analysis of rRNA genes in Vibrio fischeri indicates the presence of eight rRNA gene sets in this organism. It was found that the genes for 5S rRNA, 16S rRNA, and 23S rRNA are organized in operons in the following order: 5' end 16S rRNA 23S RNA 5S rRNA 3' end. Although the operons are homologous, they are not identical with regard to cleavage sites for various restriction endonucleases. A DNA library was constructed, and three ribosomal DNA clones were obtained. One of these clones contained an entire rRNA operon and was used as a source for subcloning. The promoter region which leads to plasmid instability was successfully subcloned into pHG165. The terminator region was subcloned into pBR322. 相似文献
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Matching the crystallographic structure of ribosomal protein S7 to a three-dimensional model of the 16S ribosomal RNA. 总被引:2,自引:1,他引:1 下载免费PDF全文
I Tanaka A Nakagawa H Hosaka S Wakatsuki F Mueller R Brimacombe 《RNA (New York, N.Y.)》1998,4(5):542-550
Two recently published but independently derived structures, namely the X-ray crystallographic structure of ribosomal protein S7 and the "binding pocket" for this protein in a three-dimensional model of the 16S rRNA, have been correlated with one another. The known rRNA-protein interactions for S7 include a minimum binding site, a number of footprint sites, and two RNA-protein crosslink sites on the 16S rRNA, all of which form a compact group in the published 16S rRNA model (despite the fact that these interactions were not used as primary modeling constraints in building that model). The amino acids in protein S7 that are involved in the two crosslinks to 16S rRNA have also been determined in previous studies, and here we have used these sites to orient the crystallographic structure of S7 relative to its rRNA binding pocket. Some minor alterations were made to the rRNA model to improve the fit. In the resulting structure, the principal positively charged surface of the protein is in contact with the 16S rRNA, and all of the RNA-protein interaction data are satisfied. The quality of the fit gives added confidence as to the validity of the 16S rRNA model. Protein S7 is furthermore known to be crosslinked both to P site-bound tRNA and to mRNA at positions upstream of the P site codon; the matched S7-16S rRNA structure makes a prediction as to the location of this crosslink site within the protein molecule. 相似文献
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Ribosomal protein-nucleic acid interactions. I. Isolation of a polypeptide fragment from 30S protein S8 which binds to 16S rRNA. 总被引:4,自引:3,他引:1 下载免费PDF全文
Within the bacterial ribosome a large number of specific protein and rRNA interactions appear to be required for assembly of the particle and its subsequent function in protein synthesis. In this communication it is shown that it is possible to isolate cyanogen bromide digestion products from ribosomal 30S protein S8 which will interact stoichiometrically with 16S rRNA. In addition to this a small binding polypeptide was generated from S8-16S rRNA complexes which were treated with proteinase K. The digestion of the complex yields a "protected" fragment of protein S8 which binds to 16S-rRNA. The isolated fragment will reassociate with 16S rRNA. It is not displaced by other 30S ribosomal proteins and blocks the binding of intact S8 to 16S rRNA. The size the possible structure of the S8 protein binding site are discussed and compared with the binding of cyanogen bromide digestion products which bind to 16S rRNA. 相似文献
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We cloned Sau3AI fragments containing the rRNA genes for Leptospira interrogans serovar canicola strain Moulton in the BamHI site of lambda EMBL3 bacteriophage DNA. Physical maps of the fragments were constructed, and the locations of the rRNA genes were determined by Southern blot hybridization and S1 protection. Each fragment of the 23S or the 16S rRNA gene contained at least one copy of the 23S or the 16S sequence. Genomic hybridization showed that there were two genes for the 23S rRNA and the 16S rRNA but only one gene for the 5S rRNA on the chromosome of L. interrogans. The results revealed the important fact that each rRNA gene is located far from the other rRNA genes. Our findings, accordingly, also suggest that these rRNA genes are expressed independently in this organism. 相似文献
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Novel approach to quantitative detection of specific rRNA in a microbial community, using catalytic DNA 总被引:3,自引:0,他引:3
We developed a novel method for the quantitative detection of the 16S rRNA of a specific bacterial species in the microbial community by using deoxyribozyme (DNAzyme), which possesses the catalytic function to cleave RNA in a sequence-specific manner. A mixture of heterogeneous 16S rRNA containing the target 16S rRNA was incubated with a species-specific DNAzyme. The cleaved target 16S rRNA was separated from the intact 16S rRNA by electrophoresis, and then their amounts were compared for the quantitative detection of target 16S rRNA. This method was used to determine the abundance of the 16S rRNA of a filamentous bacterium, Sphaerotilus natans, in activated sludge, which is a microbial mixture used in wastewater treatment systems. The result indicated that this DNAzyme-based approach would be applicable to actual microbial communities. 相似文献
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E M Orozco K E Rushlow J R Dodd R B Hallick 《The Journal of biological chemistry》1980,255(22):10997-11003
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Novel Approach to Quantitative Detection of Specific rRNA in a Microbial Community, Using Catalytic DNA 总被引:1,自引:0,他引:1
We developed a novel method for the quantitative detection of the 16S rRNA of a specific bacterial species in the microbial community by using deoxyribozyme (DNAzyme), which possesses the catalytic function to cleave RNA in a sequence-specific manner. A mixture of heterogeneous 16S rRNA containing the target 16S rRNA was incubated with a species-specific DNAzyme. The cleaved target 16S rRNA was separated from the intact 16S rRNA by electrophoresis, and then their amounts were compared for the quantitative detection of target 16S rRNA. This method was used to determine the abundance of the 16S rRNA of a filamentous bacterium, Sphaerotilus natans, in activated sludge, which is a microbial mixture used in wastewater treatment systems. The result indicated that this DNAzyme-based approach would be applicable to actual microbial communities. 相似文献
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Assembly of the 30S ribosomal subunit occurs in a highly ordered and sequential manner. The ordered addition of ribosomal proteins to the growing ribonucleoprotein particle is initiated by the association of primary binding proteins. These proteins bind specifically and independently to 16S ribosomal RNA (rRNA). Two primary binding proteins, S8 and S15, interact exclusively with the central domain of 16S rRNA. Binding of S15 to the central domain results in a conformational change in the RNA and is followed by the ordered assembly of the S6/S18 dimer, S11 and finally S21 to form the platform of the 30S subunit. In contrast, S8 is not part of this major platform assembly branch. Of the remaining central domain binding proteins, only S21 association is slightly dependent on S8. Thus, although S8 is a primary binding protein that extensively contacts the central domain, its role in assembly of this domain remains unclear. Here, we used directed hydroxyl radical probing from four unique positions on S15 to assess organization of the central domain of 16S rRNA as a consequence of S8 association. Hydroxyl radical probing of Fe(II)-S15/16S rRNA and Fe(II)-S15/S8/16S rRNA ribonucleoprotein particles reveal changes in the 16S rRNA environment of S15 upon addition of S8. These changes occur predominantly in helices 24 and 26 near previously identified S8 binding sites. These S8-dependent conformational changes are consistent with 16S rRNA folding in complete 30S subunits. Thus, while S8 binding is not absolutely required for assembly of the platform, it appears to affect significantly the 16S rRNA environment of S15 by influencing central domain organization. 相似文献