celecoxib, a specific cyclooxygenase-2 (cox-2) inhibitor, has been shown to possess antitumor activity in a variety of cancer cells. however, the antitumor activity of two synthesized cox-2 inhibitor derivatives ( a and b ) on human myeloid leukemia (k562) and breast adenocarcinoma (mcf-7) cancer cells has not been well established. this study was designed to investigate the morphological chang...

The integrase (IN) protein of the human immunodeficiency virus (HIV) is required for specific cleavage of the viral DNA termini, and subsequent integration of the viral DNA into target DNA. To identify the various domains of the IN protein we generated a series of IN deletion mutants as fusions to maltose-binding protein (MBP). The deletion mutants were tested for their ability to bind DNA, to ...

Central to the Mu transpositional recombination are the two chemical steps; donor DNA cleavage and strand transfer. These reactions occur within the Mu transpososome that contains two Mu DNA end segments bound to a tetramer of MuA, the transposase. To investigate which MuA monomer catalyzes which chemical reaction, we made transpososomes containing wild-type and active site mutant MuA. By pre-l...

Metnase (SETMAR) is a SET and transposase fusion protein that promotes in vivo end joining activity and mediates genomic integration of foreign DNA. Recent studies showed that Metnase retained most of the transposase activities, including 5'-terminal inverted repeat (TIR)-specific binding and assembly of a paired end complex, and cleavage of the 5'-end of the TIR element. Here we show that R432...

This study concerns chimeric restriction enzymes that are hybrids between a zinc finger DNA-binding domain and the non-specific DNA-cleavage domain from the natural restriction enzyme FOK:I. Because of the flexibility of DNA recognition by zinc fingers, these enzymes are potential tools for cleaving DNA at arbitrarily selected sequences. Efficient double-strand cleavage by the chimeric nuclease...

SUMMARY Escherichia coli HU, a nonsequence-specific histone- and HMG-like DNA-binding protein, was chemically converted into a series of HU-nucleases with an iron-EDTA-based cleavage moiety positioned at 16 rationally selected sites. Specific DNA cleavage patterns from each of these HU-nucleases allowed us to determine the precise localization, stoichiometry, and orientation of HU binding in th...

The formation of DNA-based nanostructures involves the binding of different kinds of ligands to DNA as well as the interaction of DNA molecules with each other. Complex formation between ligand and DNA can alter physicochemical properties of the DNA molecule. In the present work, the accessibility of DNAligand complexes to cleavage by DNase I are considered, and the exact algorithms for analysi...