Engineering of a redox protein for DNA-directed assembly.

Engineered enzyme conjugate of the small laccase enzyme from Streptomyces coelicolor and zinc finger DNA binding domain from Zif268 is demonstrated to bind double stranded DNA in a site specific manner while retaining enzymatic activity.

Design parameters for tuning the type 1 Cu multicopper oxidase redox potential: insight from a combination of first principles and empirical molecular dynamics simulations.

The redox potentials and reorganization energies of the type 1 (T1) Cu site in four multicopper oxidases were calculated by combining first principles density functional theory (QM) and QM/MM molecular dynamics (MD) simulations. The model enzymes selected included the laccase from Trametes versicolor, the laccase-like enzyme isolated from Bacillus subtilis, CueO required for copper homeostasis in Escherichia coli, and the small laccase (SLAC) from Streptomyces coelicolor. The results demonstrated good agreement with experimental data and provided insight into the parameters that influence the T1 redox potential.

High electrocatalytic activity of tethered multicopper oxidase-carbon nanotube conjugates.

Multicopper oxidases linked to multiwall carbon nanotubes via the molecular tethering reagent, 1-pyrenebutanoic acid, succinimidyl ester, displayed high bioelectrocatalytic activity for oxygen reduction.

Surface characterization and direct electrochemistry of redox copper centers of bilirubin oxidase from fungi Myrothecium verrucaria.

The key characteristics of multicopper oxidases are redox potentials of Type 1, Type 2 and Type 3 copper centers of enzymes. However, there is still a challenge to obtain a value of the redox "signature" of the enzymes. In this study, the electrochemical behavior of T1 and T2/T3 redox copper centers of bilirubin oxidase (BOD) from the fungi Myrothecium verrucaria was studied based on direct bioelectrocatalysis.

Entrapment of enzymes and carbon nanotubes in biologically synthesized silica: glucose oxidase-catalyzed direct electron transfer.

This work demonstrates a new approach for building bioinorganic interfaces by integrating biologically derived silica with single-walled carbon nanotubes to create a conductive matrix for immobilization of enzymes. Such a strategy not only allows simple integration into biodevices but presents an opportunity to intimately interface an enzyme and manifest direct electron transfer features. Biologically synthesized silica/carbon nanotube/enzyme composites are evaluated electrochemically and characterized by means of X-ray photoelectron spectroscopy.

A new electro-optical approach to rapid assay of cell viability.

A new electro-optical (EO) approach was developed and applied to rapidly assay cell viability by using phage M13K07. Since phage M13K07 can replicate only in living bacteria and cannot replicate in the presence of inhibitors, the difference between the EO signals obtained in the presence and absence of the phage can be used as an important factor for evaluating cell viability. Variation in the electrophysical parameters of Escherichia coli XL-1 during its interaction with phage M13K07 was studied under exposure of the cells to various inhibitors of cellular metabolism.

Studies of Listeria monocytogenes-antibody binding using electro-orientation.

An electro-optical (EO) approach has been used for studies of Listeria monocytogenes-antibody binding. The EO analyzer, which has been developed at the State Research Center for Applied Microbiology, Obolensk, was used as a basic instrument for EO measurements. AC electro-kinetic effects depend on dielectric properties of bioparticles, their composition, morphology, the medium, and the frequency of applied electrical field.

Electrooptical analysis of the Escherichia coli-phage interaction.

This article describes electrooptical (EO) characterization of biospecific binding between the bacterium Escherichia coli XL-1 and the phage M13K07. The electrooptical analyzer (ELUS EO), which has been developed at the State Research Center for Applied Microbiology, Obolensk, Russia, was used as the basic instrument for EO measurements. The operating principle of the analyzer is based on the polarizability of microorganisms, which depends strongly on their composition, morphology, and phenotype.

Nucleic acid approaches for detection and identification of biological warfare and infectious disease agents.

Biological warfare agents are the most problematic of the weapons of mass destruction and terror. Both civilian and military sources predict that over the next decade the threat from proliferation of these agents will increase significantly. In this review we summarize the state of the art in detection and identification of biological threat agents based on PCR technology with emphasis on the new technology of microarrays.

Flow-through immunofiltration assay system for rapid detection of E. coli O157:H7.

A flow-through amperometric immunofiltration assay system based on disposable porous filter-membranes for rapid detection of Escherichia coli O157:H7 has been developed. The analytical system utilizes flow-through, immunofiltration and enzyme immunoassay techniques in conjunction with an amperometric sensor. The parameters affecting the immunoassay such as selection of appropriate filter membranes, membrane pore size, antibody binding capacity and the concentrations of immunoreagents were investigated and optimized.

Interactions of calmodulin with metal ions and with its target proteins revealed by conformation-sensitive monoclonal antibodies.

Two monoclonal antibodies (mAbs) raised against bovine calmodulin (CaM), CAM1 and CAM4, enable one to monitor conformational changes that occur in the molecule. The interaction of CAM1 with CaM depends on the Ca2+ occupancy of its Ca(2+)-binding sites. CAM4, in contrast, interacts with CaM in a Ca(2+)-independent manner, interacting with both holoCaM and EGTA-treated CaM to a similar extent.

An amperometric enzyme-channeling immunosensor.

This paper presents a new disposable amperometric, enzyme-channeling immunosensor for a quantitative, rapid, separation-free enzyme immunoassay (EIA) that can be used in clinical diagnostics, as well as in biomedical, biochemical, and environmental research. The sensor consists of a disposable, polymer-modified, carbon electrode on which enzyme 1 is coimmobilized with a specific antibody that binds the corresponding antigen in a test solution. The solution also contains a conjugate of enzyme 2.

A one-step, separation-free amperometric enzyme immunosensor.

A new one-step, separation-free, amperometric enzyme immunosensor is described. The sensor consists of an antibody electrode that is low cost, disposable, and operates without washing or separation steps. The immunosensor combines the following signal-amplification systems: enzyme-channeling immunoassay; accumulation of the redox mediators (I2/I-); cyclic regeneration of an enzyme (peroxidase) substrate at the (polyethylenimine) polymer/electrode interface; and control of the hydrodynamic conditions at the interface of the antibody electrode.