Redox-active lipid-incorporating proteins as a novel immobilisation technique

Synthesis of amphiphilic seleninic acid derivatives with considerable activity against cellular membranes and certain pathogenic microbes

Selenium compounds play a major role in Biology, where they are often associated with pronounced antioxidant activity or toxicity. Whilst most selenium compounds are not necessarily hazardous, their often selective cytotoxicity is interesting from a biochemical and pharmaceutical perspective. We have synthesized a series of amphiphilic molecules which combine a hydrophilic seleninic acid head group - which at the same time serves as thiol-specific warhead - with a hydrophobic tail. These molecules possess a surface activity similar to the one of SDS, yet their biological activity seems to exceed by far the one of a simple surfactant (e.g. SDS) or seleninic acid (e.g. phenyl seleninic acid). Such compounds effectively haemolyse Red Blood Cells and exhibit pronounced activity against Saccharomyces cerevisiae. From a chemical perspective, the seleninic warheads are likely to attack crucial cysteine proteins of the cellular thiolstat.

Manipulating redox systems: application to nanotechnology

Redox proteins and enzymes are attractive targets for nanobiotechnology. The theoretical framework of biological electron transfer is increasingly well-understood, and several properties make redox centres good systems for exploitation: many can be detected both electrochemically and optically; they can perform specific reactions; they are capable of self-assembly; and their dimensions are in the nanoscale. Great progress has been made with the two main approaches of protein engineering: rational design and combinatorial synthesis. Rational design has put our understanding of the structure-function relationship to the test, whereas combinatorial synthesis has generated new molecules of interest. This article provides selected examples of novel approaches where redox proteins are "wired up" in efficient electron-transfer chains, are "assembled" in artificial multidomain structures (molecular Lego), are "linked" to surfaces in nanodevices for biosensing and nanobiotechnological applications.