Self-assembly of electron transport protein using oligonucleotide hybridization

In order to construct a supramolecular architecture composed of an electron transport protein and oligonucleotide, two complementary oligonucleotides were appended to cytochrome b(562) (b562) and its cofactor heme as 'tab for sticking'. His 63 of b562, located at the opposite side of the heme crevice was replaced with Cys to generate b562-SH. A 24-mer linker oligonucleotide (LO) was successfully linked through the Cys 63 residue to produce b562-LO. Moreover. the complementary oligonucleotide to LO (cLO) was appended to the heme propionate to create heme-cLO. The apoprotein of b562-SH was immobilized on the sensor surface by disulfide exchange reaction. The heme-cLO was incorporated into the immobilized apo b562-SH by the heme reconstitution, and then b562-LO was integrated on that surface by hybridization. All the self-assembly processes of these molecules by non-covalent bonding interactions were confirmed with the surface plasmon resonance biosensor. The utilization of DNA hybridization and/or apoprotein-cofactor interaction may allow a new strategy to construct a molecular electronic device. (C) 2002 Elsevier Science B.V. All rights reserved.