Electrochemical and infrared spectroscopic analysis of the interaction of the CuA domain and cytochrome c552 from Thermus thermophilus

AbstractThe hydrophobically guided complex formation between the CuA fragment from Thermus thermophilus ba3 terminal oxidase and its electron transfer substrate, cytochrome c552, was investigated electrochemically. In the presence of the purified CuA fragment, a clear downshift of the c552 redox potential from 171 to 111mV±10mV vs SHE′ was found. Interestingly, this potential change fully matches complex formation with this electron acceptor site in other oxidases guided by electrostatic or covalent interactions. Redox induced FTIR difference spectra revealed conformational changes associated with complex formation and indicated the involvement of heme propionates. This article is part of a Special Issue entitled: 17th European Bioenergetics Conference (EBEC 2012)