Replication of human immunodeficiency virus type 1 (HIV-1) requires specific interactions of the Tat protein with the transactivation responsive region (TAR) RNA. Tat-TAR RNA Interaction is mediated by a short arginine-rich domain of the protein. Disruption of this interaction could, in theory, create a state of complete viral latency. Here, four novel 6-amino-6-deoxytrehalose guanidinoglycoside derivatives (10 and 13

Abstract To study the interactions of these compounds with calf thymus DNA(CT-DNA), seven b-carboline-3-carboxamides were designed and synthesized. The interactions of these compounds with CT-DNA were determined by the viscometric titration assay and Tm (melting temperature) value assay. Binding strengths were evaluated by spectrophotometric titration experiment and microcalorimetric measurement. The interactions of these compounds were tested with CT-DNA. It was showed that all of these compounds were able to change the Tm value of CT-DNA. The results of viscometric titration assay indicated that these compounds interacted with CT-DNA by intercalation. Spectrophotometric titration experiment showed that the binding strengths of these compounds with CT-DNA were different, which was well in agreement with the cell culture results. The binding was driven by entropy according to the results of the microcalorimetric measurement. This series of b-carboline-3-carboxamides is DNA targeting compounds. Their obvious antitumor biological effect is based on the intercalation with DNA base-pairs.

The complex [Mn(L)(NO) (HO)] (1) (L52H-5-hydroxy-1, 2, 5-oxadiazo[3, 4-f]1,10-phenanthroline) was synthesized and character-3222 ized 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 P2/n, Z54, a 57.432 (2) A, b59.582(3) A, c 523.445(7) A, b 590.519 (5)8. The Mn atom in 11 is hexa-coordinated in a distorted octahedral arrangement by two N atoms of the ligand L and four O atoms of two water molecules and two nitrate anions. Biological tests in vitro showed that 1 has significant antitumor activity against HL-60, KB, Hela and BGC-823 cells. The interaction of 1 with calf thymus DNA was investigated by absorption titration, thermal denaturation and viscosity measurements. The results suggest that 1 binds with DNA by intercalating via the ligand L.

The novel analogues 11

A series of 3-substituted-β-carboline derivatives was synthesized from L-tryptophan. The intercalating binding mode of these compounds with DNA, the effects of the flexible alkylamine side chain on the intercalating a bility and their antitumor activity were studied, which agreed well with the molecular modeling results.