Towards a Chemical Etiology of Nucleic Acid Structure

To Leslie E. Orgel, arbiter elegantiarum of contemporary origin-of-life science and far-sighted pioneer of non-enzymic molecular replication, on the occasion of his 70th birthday, with cordial congratulations and best wishes.In the sequel of some general remarks on a chemical etiology of nucleic-acid structure, the paper presents a reproduction of the sequence of slides which were shown in the author's lecture Pyranosyl-RNA at the 8. ISSOL Conference in Orléans. Each slide figure is accompanied by a short explanatory comment.     

Progress Towards a Submonomer Synthesis of Peptide Nucleic Acid

Abstract

We report recent developments in the optimization of a submonomer synthesis of peptide nucleic acid based on the Fukuyama-Mitsunobu reaction. The key steps in the submonomer synthesis are the installation of an appropriately protected 2-aminoethyl group on the α-nitrogen of an amino acid and its subsequent acylation with a protected nucleobase derivative. The aggressive alkylation conditions require a scheme of maximal protection for the nucleobases and that is proposed herein for the pyrimidines.     

多肽核酸

通过计算机模型设计出一种以肽骨架取代ＤＮＡ中脱氧核糖磷酸酯骨架的ＤＮＡ类似物．实验已证明其与互补寡核苷酸的结合具有高度的特异性．综述了其合成、杂交性及在分子生物学等方面的应用．     

Peptide-Templated Nucleic Acid Ligation

Abstract Short oligonucleotide and peptide replicators have been described. To determine whether cross-replication could have occurred between such systems, we have attempted to show that peptides can specifically template the ligation of nucleic acids. A complex between a 35-mer anti-Rev RNA aptamer and a 17-mer arginine-rich motif (ARM) peptide from the HIV-1 Rev protein served as a model system. Aptamer half-molecules were activated for ligation via two activation chemistries, representing two distinct kinetic possibilities for early replicators. Cyanogen bromide activation was transient relative to oligonucleotides that terminated with a 5′-iodine and a 3′phosphorothioate, respectively. The Rev ARM specifically enhanced the degree or rate of ligation by both methods: there was a 10-fold increase in the production of full-length aptamer in the presence of cyanogen bromide and a 5.9- to 7.6-fold enhancement in the rate of ligation for stably activated aptamer half-molecules. These results support the possibility that life could have originated with peptide replicators and transitioned to nucleic acid replicators or that peptide and nucleic acid replicators could have been interdependent.     

Fluorinated Peptide Nucleic Acid

Abstract

The fluorinated olefinic peptide nucleic acid analogue (F-OPA) monomer containing the base thymine was synthesised in 13 steps. PNAs containing this unit were prepared and their pairing properties assessed by means of UV-melting experiments.     

核酸纯化柱提取核酸定量检测丙型肝炎病毒RNA的临床应用

目的:探究核酸纯化柱提取核酸定量检测血浆标本中丙型肝炎病毒核糖核酸(HCV-RNA)的临床应用效果。方法:将2013年8-11月期间我院600例抗-HCV阳性丙肝患者的样本,按随机字数表法分为研究组对照组各300例,分别采用核酸纯化柱和酚-氯仿提取法检测,采用实时荧光定量聚合酶链反应(FQ-PCR)技术定量检测两组HCV-RNA水平。结果:研究组检测阳性率为87.67%(263/300),显著高于和对照组的54.0%(162/300),差异有统计学意义(X2=82.296,P=0.000);两组HCV-RNA检测水平差异无统计学意义(u=1.721,P=0.067)。结论:核酸柱提法定量检测血浆HCV-RNA操作简单、快速,分离效率高,容易掌握,值得临床推广。     

Berenil Complexation with a Nucleic Acid Triple Helix

Abstract

The interaction of berenii molecule, a minor groove binding drug, with T-A-T triple helix and A-T double helix was studied using circular dichroism spectroscopy and thermal denaturation. The triple helix was made by an oligonucleotide (dA)₁₂?x-(dT)₁₂?x-(dT)₁₂, where x is a hexaethylene glycol chain bridged between the 3′ phosphate of one strand and the 5′ phosphate of the following strand. This oligonucleotide is able to fold back on itself to form a very stable triplex. Circular dichroism spectroscopy demonstrates that berenil can bind to the triple helical structure. Spectral analysis shows that in the same ionic strength the drug bound to a double-stranded structure exhibits a conformation and an environment close to those observed in triple-stranded structure. The influence of the ionic strength on the interaction between the berenil molecule and the 36-mer is clearly demonstrated. We showed that when no NaCl salt is added in the buffer the triplex form of (dA)₁₂?x-(dT)₁2-x-(dT)₁₂ is stabilized by berenil whereas it is destabilized slightly by the dye when NaCl concentration is 1 M.     

Liquid Phase Synthesis of Peptide Nucleic Acid (or Polyamide Nucleic Acid) Dimers

Abstract

The liquid phase synthesis of “polyamide nucleic acid” (PNA) dimers containing the purine nucleic acid bases adenine and guanine has been achieved in good yields. This strategy was elaborated in order to circumvent difficult direct coupling of protected PNA monomers. This method can be applied to the liquid phase synthesis of short protected polyPNAs fragments, which can then selectively be deprotected.     

Nucleobase Modified Peptide Nucleic Acid

Abstract

The Pd⁰/Cu^I catalyzed cross-coupling of terminal alkynes onto peptide nucleic acid monomers or submonomers bearing iodinated nucleobases has been utilized as a route to base-modified oligomers. Both 5-iodouracil and 5-iodocytosine derivatives undergo the cross-coupling to give the expected products in moderate to good yields. However, depending on the particular substrates and reaction conditions, the cross-coupling may be followed by a ring closing reaction to give the fluorescent furano- and pyrrolo-fused uracil and cytosine derivatives, respectively.     

核酸检测技术进展及其在SARS-CoV-2核酸检测中的应用

2020年初至今,新型冠状病毒肺炎(COVID-19)疫情仍在全球多个国家流行,给全球公共卫生安全造成了严重威胁.中国在应对COVID-19的实践中,最先完成病毒核酸测序并共享序列信息,最早有效控制疫情蔓延、恢复生产,并在病毒作用人体机制研究、疫苗研发、中和性抗体发现等环节均处于世界前沿.其中,针对病毒核酸的检测工作—...     

Locked Nucleic Acids: Promising Nucleic Acid Analogs for Therapeutic Applications

Locked Nucleic Acid (LNA) is a unique nucleic‐acid modification possessing very high binding affinity and excellent specificity toward complementary RNA or DNA oligonucleotides. The remarkable properties exhibited by LNA oligonucleotides have been employed in different nucleic acid‐based therapeutic strategies both in vitro and in vivo. Herein, we highlight the applications of LNA nucleotides for controlling gene expression.     

核酸提取方法进展

核酸提取是分子生物学的基本方法,也是核酸诊断中最关键的方法,它是下游诊断、分析和制备的前提。过去的核酸提取方法繁琐费时且有限。目前,核酸提取方法已经取得了较大进步。本文综述了核酸提取方法的进展情况,包括传统的基于溶液的抽提方法、现在常用的柱提取法、正兴起的多效生物分子抽提法和自动化抽提系统等。多效生物分子抽提法、自动抽提系统的微型化和完全自动化或者它们的组合是核酸提取技术未来发展的方向。     

生物技术产品中的残核酸

从事基因工程产品研究和开发的人经常碰到一个问题 :如何检测这类产品中残留的核酸 ?据说有关管理部门本身也没有提出相关的技术和检测标准 ,而让申请人自行决定 ,再由他们核准。因此 ,我在阅读文献时特别关注这些问题 ,果然看到一些相关的材料 ,不敢私藏 ,愿意在此与有关人士分享。构建重组的微生物和哺乳动物细胞时都用到重组ＤＮＡ技术。为了得到永生的 ,有生产价值的细胞株 (包括有些细菌菌株 ,下同 )需要将癌基因的ＤＮＡ序列整合入生产性细胞 ;为了得到到高产的细胞株 ,往往利用病毒的启动子等序列。但是 ,这样的ＤＮＡ序列一旦被掺入…     

Fourth Rank Immobile Nucleic Acid Junctions

Abstract

An immobile nucleic acid junction composed of four dodecanucleotides has been designed according to principles of minimum symmetry aided by equilibrium calculations, and has been synthesized by automated phosphotriester techniques. We can demonstrate its tetrameric character and its 1:1:1:1 stoichiometry by gel electrophoresis. Thermal denaturation monitored by ultraviolet hyperchromism indicates that the complex is stable relative to its component arms. High resolution NMR spectroscopy suggests that this junction exists in more than one conformer at room temperature. The data from this junction are compared with the data from a similar junction composed of four hexadecanucleotides.     

Lna (Locked Nucleic Acid)

Abstract

LNA (Locked Nucleic Acid) forms duplexes with complementary DNA, RNA or LNA with unprecedented thermal affinities. CD spectra show that duplexes involving fully modified LNA (especially LNA:RNA) structurally resemble an A-form RNA:RNA duplex. NMR examination of an LNA:DNA duplex confirm the 3′-endo conformation of an LNA monomer. Recognition of double-stranded DNA is demonstrated suggesting strand invasion by LNA. Lipofectin-mediated efficient delivery of LNA into living human breast cancer cells has been accomplished.