Apotransferrin (apo Tf)  in 0.1 M N-(2hydroxyethyl)piperazine-N2-ethanesulfanic acid at 25 ˚C  and pH 7.4 has been titrated with acidic solution of Tb3+. The binding of Tb3+ at  the two specific metal-binding sites of transferrin was followed from the changes in the difference UV spectra at 245 nm. The molar absorptivity per binding site for Tb3+...

Topoisomerase I (topo I) is needed for efficient initiation of simian virus 40 (SV40) DNA replication and for the formation of completed DNA molecules. Two distinct binding sites for topo I have been previously mapped to the N-terminal (residues 83 to 160) and C-terminal (residues 602 to 708) regions of T antigen. By mutational analysis, we identified a cluster of six residues on the surface of...

The promoter of the murine thymidine kinase gene contains a binding site for transcription factor E2F. Using cell lines (3T3-LT) conditionally expressing polyomavirus large T antigen from a hormone-responsive promoter and reporter gene constructs carrying the thymidine kinase promoter with intact or mutated E2F sites, we show that this E2F site is the target for trans activation by the viral pr...

Processed antigen reacts selectively with lymphocytes bearing .appropriate surface immunoglobulin molecules resulting in the clonal proliferation of these cells, produc­ing circulating immunoglobulin (humoral immunity) or non-circulating immunoglobulins (cellular immunity).  High levels of circulating immunoglobulins (lgM & lgG) occur in protozoa and helminths infections. Reaginic antibodies a...

interference with microtubule polymerization results in cell cycle arrest leading to cell death. colchicine is a well-known microtubule polymerization inhibitor which does so by binding to a specific site on tubulin. a set of 3',4'-bis (substituted phenyl)-4'h-spiro[indene-2,5'-isoxazol]-1(3h)-one derivatives with known antiproliferative activities were evaluated for their t...

A single antibody was shown to adopt different binding-site conformations and thereby bind unrelated antigens. Analysis by both x-ray crystallography and pre-steady-state kinetics revealed an equilibrium between different preexisting isomers, one of which possessed a promiscuous, low-affinity binding site for aromatic ligands, including the immunizing hapten. A subsequent induced-fit isomerizat...

In the last decades researchers had focused on developing a vaccine against tick based on protective antigen. Recombinant vaccines based on concealed antigen from Boophilus microplus have been developed in Australia and Cuba by the name of TICKGARD and GAVAC (De La Fuente and Kocan, 2006). Further studies on this antigen have shown some extent of protection against other species (De Vos et al.,...

the binding behavior of a competitive inhibitor, n-phenylbenzhydroxamic acid (bha) against horseradish peroxidase (hrp) was studied in order to understand and predict the interaction mechanism of hydrogen donors with the enzyme. the dissociation constants of the complexes of hrp-bha, hrp-donor and hrp-bha-azide were estimated at specified conditions by difference spectroscopy. the binding site ...

Horseradish peroxidase (HRP), has gained significant interests in biotechnology, especially in biosensor field and diagnostic test kits. Hence, its solvent-exposed lysine residues 174, 232, and 241 have been frequently modified with the aim of improving its stability and catalytic efficiency. In this computational study, we investigated the effects of Lys-to-Glu substitutions on HRP structure t...