Reverse gyrase is a unique hyperthermophile-specific DNA topoisomerase that induces positive supercoiling. It is a modular enzyme composed of a topoisomerase IA and a helicase domain, which cooperate in the ATP-dependent positive supercoiling reaction. Although its physiological function has not been determined, it can be hypothesized that, like the topoisomerase-helicase complexes found in eve...

Abstract RNA polymerase inhibition plays an important role in the regulation of transcription response to environmental changes and virus-host relationship. Here we present high-resolution structures two such RNAP-inhibitor complexes that provide structural bases underlying RNAP archaea. The Acidianus two-tailed virus encodes RIP factor binds inside DNA-binding channel RNAP, inhibiting by occlu...

Killer lymphocyte granzyme (Gzm) serine proteases induce apoptosis of pathogen-infected cells and tumor cells. Many known Gzm substrates are nucleic acid binding proteins, and the Gzms accumulate in the target cell nucleus by an unknown mechanism. In this study, we show that human Gzms bind to DNA and RNA with nanomolar affinity. Gzms cleave their substrates most efficiently when both are bound...

Copper-phenanthroline complexes oxidatively damage and cleave nucleic acids. Copper bis-phenanthroline and copper complexes of mono- and bis-phenanthroline conjugates are used as research tools for studying nucleic acid structure and binding interactions. The mechanism of DNA oxidation and cleavage by these complexes was examined using two copper-phenanthroline conjugates of the sequence-specif...

New symmetrical acyclic binuclear copper (II) complexes [CuL](ClO4)2 1 and 2 were synthesized by template method, from bicompartmental ligand 2,6-bis((E)-(2-(2aminoethylamino)ethylimino)methyl)-4-methylphenol (L) and 2-((7E)-(2-((Z)-2-((naphthalen-1-yl) methyleneamino)ethylamino)ethylimino)methyl)-6-((9E)-(2-((Z)-2-((naphthalen-1-yl)methyleneamino) ethylamino)ethylimino) methyl)-4-methylphenol ...

The synthesis and the investigation of the Cu(II)-binding, the DNA-binding, and the DNA-damaging properties of a conjugate between the benzo[b]quinolizinium ion and the bis(pyridin-2-ylmethyl)amino receptor are presented. Photometric and fluorimetric titrations as well as CD spectroscopic analysis reveal that the 9-bis(pyridin-2-ylmethyl)aminobenzo[b]quinolizinium ligand intercalates into DNA (...

Deoxyribonucleic acid is the site of storage and retrieval of genetic information through interaction with proteins and other small molecules. Hydrolysis of the phosphodiester bond of DNA is of critical importance at several stages in a cell cycle. Thus, the development of metal complexes that cleave nucleic acids hydrolytically at physiological conditions is of great interest in the field of a...

Creating endonucleases with novel sequence specificities provides more possibilities to manipulate DNA. We have created a chimeric endonuclease (CH-endonuclease) consisting of the DNA cleavage domain of BmrI restriction endonuclease and C.BclI, a controller protein of the BclI restriction-modification system. The purified chimeric endonuclease, BmrI198-C.BclI, cleaves DNA at specific sites in t...

I- Dmo I is a homing enzyme of the LAGLI-DADG type that recognizes up to 20 bp of DNA and is encoded by an archaeal intron of the hyperthermophilic archaeon Desulfurococcus mobilis . A combined mutational and DNA footprinting approach was employed to investigate the specificity of the I- Dmo I-substrate interaction. The results indicate that the enzyme binds primarily to short base paired regio...