Tat, an essential human immumodeficiency virus type 1 protein interact s with the t ransactivation response element (TAR) and stimulates transcription from the viral long-terminal repeat (LTR). Blockage of Tat-TAR interaction halt sviral transcription and hence replication. In recent years a numbe of studies have suggested various chemicals and/or genetic inhibitors targeting TAR RNA for inhibition of Tatactivated t ranscription. Here, we report these research works.

The complex [Mn(L)(NO3)2(H2O2)] (1) (L=2H-5-hydroxy-1, 2, 5-oxadiazo[3, 4-f]1,10-phenanthroline) was synthesized and characterized by elemental analysis, IR and UV. The crystal and molecular structure of 1 was determined by single-crystal X-ray diffraction; crystal data: light yellow, monoclinic, space group P21/n, Z=4, a=7.432(2)

A new Mn(II) complex with the planar ligand 6,7-dicycanodipyrido[2, 2-d: 29, 39-ƒ]quinoxaline (L) [MnL(NO3)(H2O)3]NO 3-CH3OH 3 (1) has been synthesized and characterized by elemental analysis, IR, TG-DTA and molar conductance. Its crystal structure was determined by X-ray diffraction, crystal data: yellow, triclinic, space group P1, Z=2, a =7.3743 (8)Å, b=11.2487 (15)Å, c=14.1655 (15)Å,α=79.412 (2)°,β=83.208(2) °, γ=80.466(2) °. The Mn atom was hexa-coordinated to form a distorted octahedral geometry by two nitrogen atoms of L and four oxygen atoms of three H2O and NO-3 in the complex. The binding mode of the complex with calf thymus DNA has also been investigated with spectrophotometric methods, viscosity and thermal denaturation measurements. The experimental results indicate that the complex intercalated into DNA base pairs via the ligand L. The intrinsic binding constant Kb values for 1 (5.00×10M-1) and L (1.65×105 M-1) were determined by absorption titration and calculated with the model of McGhee and Von Hippel. Biological tests against four different cell lines (HL-60, KB, Hela and BGC-823) in vitro showed that the complex had significant antitumor properties since the 50% inhibition concentrations (IC50) of the complex were within a μM range similar to those of antitumor 50 drug 5-fluorouracil.

整合酶（integrase）对于人免疫缺陷病毒（HIV）-1逆转录病毒的复制来说是必不可少的，因而成为抗艾滋病（AIDS）药物设计的一个理性的靶点。最近文献报道了大量具有抗整合酶活性的化合物，当前最大的挑战就是如何将这些作用于整合酶靶点的先导化合物转变成为临床上有效的抗AIDS药物。

本文对两种具有抗HIV-1活性的药物与RNA 的相互作用进行了探讨。紫外Tm测定及CD光谱结果表明，两种药物均可与polyA·polyU 相互作用，影响其构象的改变。流式细胞仪分析提示药物可不同程度地影响cos-7亚二倍体细胞含量，其中ribavirin的作用更显著。