The tetraheme cytochrome c₃ from Desulfovibrio vulgaris Miyazaki F is involved in sulphate reduction. It contains four c-type hemes covalently bound to a single polypeptides of only 107 amino acids. The protein surface is highly positively charged at physiological pH with a prevalence of lysine residues. All four hemes are bis-histidine ligated and their reduction potentials are very low, ranging form -239 to -358 mV at neutral pH. With a cyclic heme arrangement and their partial exposure to solvent, cytochrome c₃ can transfer electrons in all directions. The purpose of this work is to develop novel methods of controlling the crosslinking selectivity of proteins constructing biological “nanowires” with cytochrome c₃ modules. The crosslinking functional groups are bismaleimide derivatives and the cysteine thiol. And construction strategies involve the electrostatic selection by controlling the surface charge distribution regulating the protein crosslinking, and the use of protein-peptide recognition (i.e. Calmodulin and its binding peptide) to block/protect the crosslinking sites. The electrochemical properties of cytochrome c₃ are also exploited by covalently attaching it to active centre buried redox enzymes (i.e. cytochrome P450 BM3 heme domain) and electrodes to form unique bioelectronic components, which could facilitate the electron transfer between enzymes and electrodes.