Purine 3′:5′‐cyclic nucleotides with the nucleobase in a syn orientation: cAMP,cGMP and cIMP

Purine 3′:5′‐cyclic nucleotides are very well known for their role as the secondary messengers in hormone action and cellular signal transduction. Nonetheless, their solid‐state conformational details still require investigation. Five crystals containing purine 3′:5′‐cyclic nucleotides have been obtained and structurally characterized, namely adenosine 3′:5′‐cyclic phosphate dihydrate, C₁₀H₁₂N₅O₆P·2H₂O or cAMP·2H₂O, (I), adenosine 3′:5′‐cyclic phosphate 0.3‐hydrate, C₁₀H₁₂N₅O₆P·0.3H₂O or cAMP·0.3H₂O, (II), guanosine 3′:5′‐cyclic phosphate pentahydrate, C₁₀H₁₂N₅O₇P·5H₂O or cGMP·5H₂O, (III), sodium guanosine 3′:5′‐cyclic phosphate tetrahydrate, Na⁺·C₁₀H₁₁N₅O₇P⁻·4H₂O or Na(cGMP)·4H₂O, (IV), and sodium inosine 3′:5′‐cyclic phosphate tetrahydrate, Na⁺·C₁₀H₁₀N₄O₇P⁻·4H₂O or Na(cIMP)·4H₂O, (V). Most of the cyclic nucleotide zwitterions/anions [two from four cAMP present in total in (I) and (II), cGMP in (III), cGMP⁻ in (IV) and cIMP⁻ in (V)] are syn conformers about the N‐glycosidic bond, and this nucleobase arrangement is accompanied by C_rib—H…N_pur hydrogen bonds (rib = ribose and pur = purine). The base orientation is tuned by the ribose pucker. An analysis of data obtained from the Cambridge Structural Database made in the context of syn–anti conformational preferences has revealed that among the syn conformers of various purine nucleotides, cyclic nucleotides and dinucleotides predominate significantly. The interactions stabilizing the syn conformation have been indicated. The inter‐nucleotide contacts in (I)–(V) have been systematized in terms of the chemical groups involved. All five structures display three‐dimensional hydrogen‐bonded networks.     

Preparation of Three Decadeoxyribonucleotides Containing an Uncommon or Modified Base

Three decadeoxyribonucleotides (d-C-C-A-A-I-A-T-T-G-G, d-C-^brC-A-A-G-A-T-T-G-G and d-C-C-A-A-^mG-A-T-T-G-G) involving inosine (I), 5-bromocytidine (^brC) and 6-O-methylguanosine (^mG) were chemically synthesized based on the phosphotriester approach in milligram quantities. The procedures of full protection reaction of these uncommon or modified bases are given in detail. The phosphotriester method was then employed to synthesize all the decamers. It seems the phosphotriester method is applicable to the synthesis of oligodeoxyribonucleotide with these three odd-bases. However, slightly different procedures have to be used while deblocking the fully protected oligodeoxyribonucleotides depending upon the nature of the uncommon or modified base.     

Hydrogen bonding cooperativity of water to nucleotide recognition: structure of octadecahydrated inosine 5′-monophosphate, 2(C10H12N4O8P)·18H2O at atomic resolution

The crystal structure of an octadecahydrated complex between two inosine 5-monophosphate (IMP) has been determined at atomic resolution, which reveals the hydrogen bonding and the coordination cooperativity of water molecules to nucleotide recognition. The crystal belongs to monoclinic space group P2₁ with cell dimensions a = 8.65(1), b = 21.90(1), c = 12.37(1)Å, and = 110.38(9)°. The ribose hydroxyls, purine N7, keto(O6) bonded water molecules W1, W2, W5, W6, W8 and the phosphate bridge forming water oxygens of W4, W7, W11 appear to play an invariant role in their hydrogen bonding interactions with the IMPs. The synergistic role of the water molecules W5, W6, W8 in the purine staking domain N27W5=2.583,O16W8=2.759,O2627W6=2.723 Åhave been clearly observed for the first time. The complexation of the water molecules through variable hydrogen bonding coordination indicate their functional involvement through extensive cooperative donor-acceptor network mechanism. The occurrence of hydrogen-bonded water spines, water bridges and their interplay in the structural association of IMPs could indicate the possible viability of those aquatic centers in the biological situation.     

高效毛细管电泳技术测定肌苷口服液的含量

介绍了应用高效毛细管电泳技术测定肌苷口服液含量的方法。实验是将肌苷口服液直接进样,以硼酸－硼酸盐为缓冲溶液。实验的回收率为９５．０％～９９．８％,相关系数０．９９８５,精密度的变异系数小于５％。方法简便、快速、准确、灵敏度高。     

肌苷制剂的高效液相色谱法测定

A high performance liquid chromatographic method was established for the determination of inosine intablet,capsule and injection. Sodium benzoate can also be determined.The mobile phase consists of a mixture ofmethanol-water,30:70(V/V).Metronidazole is used as the internal standard.The analytical column is Nucleosil C_(18),7μ.The average recoveries for inosine and sodium benzoate were 99.37±0.62%and 98.83±0.44%.     

从肌苷简便合成腺苷

在不改变骨架的前提下提出一种从肌苷通过官能团转换制备腺苷的工艺方法,总收率可达62%。肌苷在醋酸钠存在下与醋酸酐发生酯化反应以92%的收率得到2′,3′,5′-三乙酰肌苷,其化合物经吡啶和三氯氧磷处理形成吡啶盐溶液,未分离直接在40℃、0.25～0.30MPa压力下进行氨解反应以67%产率制得腺苷。腺苷结构经1HNMR、MS测试技术确证。这种简便的腺苷合成方法可适合于工业化生产。     

Role of water molecules in protein-nucleic acid interactions: visualization of a model highly hydrated complex structure of Inosine 5′-monophosphate and L-Serine (2C10H13N4O8P·C3H7NO3·12H2O) at atomic resolution

The crystal structure of a dodecahydrated co-complex between two Inosine 5-monophosphate (IMP) and one L-serine, the first of its kind reported, has been determined at atomic resolution by X-ray crystallographic methods. The crystal belongs to a monoclinic space group, P2₁, with the cell dimensionsa=8.695(7),b=21.898(6),c=12.374(3)Å, =110.59(3)°. This structure reveals the recognition mechanism of serine to the nucleotides through direct and water-mediated hydrogen bonds. The phosphate oxygen (O22) seems to prefer the nonspecific interaction with the functional sites of serine (N...O22=2.735, OG...O22=2.970, O1...O22 =3.121 Å), whereas the bases prefer specific (N17...N=3.199, N23...O2=2.784 Å) bondings. The solvent-mediated hydrogen bonds N17...W3...N27 endow extra stabilization to the stacked bases. The presence of hydrogen-bonded water spines and their interplay in the specific and nonspecific bindings with potential ligands indicate the functional involvement of solvent molecules through cooperative donor-acceptor network and could act as viable centers of intricate interactions in protein-DNA complexation processes.     

虎纹捕鸟蛛毒中次黄嘌吟核苷的分离与鉴定

本文从虎纹捕鸟蛛(Selenocosmia hu wena)粗毒中经高效液相色谱分离纯化出一种组分,通过场解吸质谱(FDMS)和电子电高质谱(EIMS)鉴定为次黄嘌呤核苷,其含量为3.9%.同时,进一步用标准样品进行紫外、液相色谱对照验证,并对次黄嘌呤核苷以毒液中的一种成分的形式存在的作用进行了简单的讨论.     

褶合光谱法测定肌苷口服液中的肌苷含量

建立褶合光谱法测定肌苷口服液中肌苷含量的方法。方法的线性范围为6.00-14.00μg/ml，线性回归方程为Qj=0.004233c-0.002597，相关系数r=0.99999，平均回收率为99.99%，RSD为0.20%。t检验结果证明，该方法与吸光系数法之间无显著性差异。该方法简便、快速，用于实际样品分析，结果准确、可靠。