Journal articles

A unique sensing platform, comprising an electromagnetic field detector and an acoustic resonator, has been used as a wireless system for remote sensing of biorecognition events. The MARS (Magnetic Acoustic Resonator Sensor) technique has proven useful for detecting the formation of protein multilayers derived from specific binding phenomena. The technique enables multifrequency analysis, without the need of electrodes attached to the sensing element, and also facilitates the in situ surface modification of the substrate for antibody attachment.

A novel toroidal coil geometry able to induce remote acoustic waves in quartz crystals has been evaluated for the development of (bio)sensors. Remote acoustic generation in air was obtained for two alternative toroidal coils, with corresponding electrical impedance changes of 40 Omega for a PDMS- and 140 Omega for a ferrite-supported toroid respectively.

Firefly luciferase catalyses a two-step reaction, using ATP-Mg2+, firefly luciferin and molecular oxygen as substrates, leading to the efficient emission of yellow-green light. We report the identification of novel luciferase mutants which combine improved pH-tolerance and thermostability and that retain the specific activity of the wild-type enzyme. These were identified by the mutagenesis of solvent-exposed non-conserved hydrophobic amino acids to hydrophilic residues in Photinus pyralis firefly luciferase followed by in vivo activity screening.

This paper reports experimental developments in the construction and operation of a single-mode fibre-optic evanescent wave biosensor using an exposed core silica single-mode fibre embedded in a silica block. The device was able to monitor the concentration of a blue dye, Procion Blue MX-G, in overlayers of various refractive indices. The practicality of such a biosensor has been demonstrated with a colorimetric enzyme assay system.

Affinity chromatography is ideally suited to the purification of pharmaceutical proteins due to its unique bio-specificity characteristics. Tailor-made affinity ligands that represent a promising class of synthetic affinity ligands have been developed to target specific proteins and designed to mimic peptidal templates, natural biological recognition motifs, or complementary surface-exposed residues. These biomimetic ligands have been generated by a combination of rational design, combinatorial library synthesis, and subsequent screening of potential leads against target proteins.

A constitutive NAD(+)-linked alcohol dehydrogenase was purified 338-fold from cells of Pseudomonas maltophilia MB11L grown on glucose. Maximum activity was observed with cyclic and linear secondary alcohols, with little activity seen against primary or aromatic alcohols. Substrate oxidation activity was maximal at pH 10.0, while substrate reduction was optimal at pH 4.5. The Km values for propan-2-ol, NAD+ and acetone were 87, 413 and 143 microM respectively. The enzyme is a tetramer with subunit Mr of approximately 44,000.

Affinity chromatography represents a promising technique for decoding the proteomics universe. While conventional affinity purification is being used in conjunction with two-dimensional electrophoresis (2D-PAGE) and mass spectrometry (MS) for the study of proteomes and subproteomes, scientists are still confronted with the need for specific and tailor-made affinity ligands to target desired groups and families of proteins.

A combination of rational design based on mimicking natural protein-carbohydrate interactions and solid-phase combinatorial chemistry has led to the identification of an affinity ligand which displays selectivity for the mannose moiety of glycoproteins. The ligand was initially identified as 32/18, a triazine scaffold substituted with 2-acetylpyrrole (32) and 5-aminoindan (18).

The reversible phosphorylation of proteins regulates many biological processes. Despite the technological advances in the enrichment and detection of phosphorylated proteins, the currently available techniques still struggle with the complexity of the human proteome. The aim of this review is to highlight the molecular recognition elements of the interaction between phosphorylated proteins and peptides and pTyr or pSer/Thr-binding domains.

A transducer format that replaces the electrode of an acoustic resonator with a planar spiral coil is used to extract multifrequency spectral information from adsorbed protein films. Both amorphous silica and crystalline piezoelectric resonators are driven to resonance by forces induced across an air gap by magnetic direct generation and piezoelectric excitation induced by the electromagnetic field of the coil.