Switching an O2 sensitive glucose oxidase bioelectrode into an almost insensitive one by cofactor redesign.

In the 5-8 mM glucose concentration range, of particular interest for diabetes management, glucose oxidase bioelectrodes are O2 dependent, which decrease their efficiencies. By replacing the natural cofactor of glucose oxidase, we succeeded in turning an O2 sensitive bioelectrode into an almost insensitive one.

Recombinant glucose oxidase from Penicillium amagasakiense for efficient bioelectrochemical applications in physiological conditions.

GOX is the most widely used enzyme for the development of electrochemical glucose biosensors and biofuel cell in physiological conditions. The present work describes the production of a recombinant glucose oxidase from Penicillium amagasakiense (yGOXpenag) displaying a more efficient glucose catalysis (k(cat)/K(M)(glucose)=93 μM⁻¹ s⁻¹) than the native GOX from Aspergillus niger (nGOXaspng), which is the most industrially used (k(cat)/K(M)(glucose)=27 μM⁻¹ s⁻¹). Expression in Pichia pastoris allowed easy production and purification of the recombinant active enzyme, without overglycosylation.

An improved glucose/O2 membrane-less biofuel cell through glucose oxidase purification.

A key objective in any bioelectrochemical systems is to improve the current densities and mass transport limitation. Most of the work is focused on increasing the specific surface of the electrodes or improving the electron transfer between enzymes and electrodes. However, nothing is said about the comparison of purified and non-purified enzyme and their effects on the biosensor efficiency.

Modulation of E-cadherin monomer folding by cooperative binding of calcium ions.

Classical cadherins are transmembrane glycoproteins involved in calcium-dependent cell-cell adhesion. Calcium ions are coordinated at the interface between successive modules of the cadherin ectodomain and are thought to regulate the adhesive interactions of cadherins when present at millimolar concentrations. It is widely accepted that calcium plays a critical role in cadherin-mediated cell-cell adhesion, but the nature of cadherin-calcium binding remains a matter of debate.

Calcium dependence of aequorin bioluminescence dissected by random mutagenesis.

Aequorin bioluminescence is emitted as a rapidly decaying flash upon calcium binding. Random mutagenesis and functional screening were used to isolate aequorin mutants showing slow decay rate of luminescence. Calcium sensitivity curves were shifted in all mutants, and an intrinsic link between calcium sensitivity and decay rate was suggested by the position of all mutations in or near EF-hand calcium-binding sites.

Thermostable mutants of the photoprotein aequorin obtained by in vitro evolution.

Aequorin is a photoprotein that emits light upon binding calcium. Aequorin mutants showing increased intensity or slow decay of bioluminescence were isolated by in vitro evolution combining DNA shuffling and functional screening in bacteria. Luminescence decay mutants were isolated at the first round of screening and carried mutations located in EF-hand calcium binding sites or their vicinity.

[Molecular aspects of cadherin-mediated cell adhesion: the first moments of the interaction].

Cadherins play a major role in the development and maintenance of all solid tissues. These transmembrane glycoproteins are responsible for calcium-dependent homophilic cell interactions. Recently, many different experimental approaches have been used to untangle the molecular basis of cadherin-mediated adherence.