You are investigating the energy production in a thermophilic bacterium isolated from Old Faithful. In the course of your studies, you discover a new coenzyme, BIF. Meticulous experiments reveal that this bacterium produces BIFH2, NADH, and FADH2 in substrate oxidation reactions and regenerates the oxidized form of these coenzymes in the presence of O2 via an electron transport system.
In addition to the three coenzymes mentioned above, five cytochromes appear to be involved in electron transport. You wish to map the pathway of electron transport in this bacterium and you know that this is possible since the oxidized and reduced states of all 8 components mentioned above can be distinguished experimentally.
In your effort to elucidate the position of BIF within the pathway, the following are determined: 1) the steady-state level of oxidation of each component in the presence of substrates and O2 and 2) the degree of oxidation of each component in the presence of substrates, O2, and inhibitors of electron transport. Your results are shown in the table below (note: +++ = fully oxidized & — = fully reduced; Cyt 1, Cyt 2, etc. indicate cytochrome 1, 2, etc.):
See attached file for oxidation state chart
From these data, draw a diagram of the most likely pathway for electron transport in this organism. You need not show where the inhibitors block the pathway but, if you do, that’s ok as well. Hint: the pathway of electron flow can be linear or branched.