Redox proteins and enzymes are attractive targets for nanobiotechnology. Th
e theoretical framework of biological electron transfer is increasingly wel
l-understood, and several properties make redox centres good systems for ex
ploitation: many can be detected both electrochemically and optically; they
can perform specific reactions; they are capable of self-assembly; and the
ir dimensions are in the nanoscale. Great progress has been made with the,t
wo main approaches of protein engineering: rational design and combinatoria
l synthesis. Rational design has put our understanding of the structure-fun
ction relationship to the test, whereas combinatorial synthesis has generat
ed new molecules of interest. This article provides selected examples of no
vel approaches where redox proteins are 'wired up' in efficient electron-tr
ansfer chains, are 'assembled' in artificial multidomain structures (molecu
lar Lego), are 'linked' to surfaces in nanodevices for biosensing and nanob
iotechnological applications.