Analyzing the electrogenicity of cytochrome c oxidase

作者：Kim Ilsoo; Warshel Arieh^*

来源：Proceedings of the National Academy of Sciences of the United States of America, 2016, 113(28): 7810-7815.

DOI：10.1073/pnas.1608118113

• electrogenicity
• membrane potential
• proton transfer
• electron transfer

Measurements of voltage changes in response to charge separation within membrane proteins can offer fundamental information on spectroscopically "invisible" steps. For example, results from studies of voltage changes associated with electron and proton transfer in cytochrome c oxidase could, in principle, be used to discriminate between different theoretical models describing the molecular mechanism of proton pumping. Earlier analyses of data from these measurements have been based on macroscopic considerations that may not allow for exploring the actual molecular mechanisms. Here, we have used a coarse-grained model describing the relation between observed voltage changes and specific charge-transfer reactions, which includes an explicit description of the membrane, the electrolytes, and the electrodes. The results from these calculations offer mechanistic insights at the molecular level. Our main conclusion is that previously assumed mechanistic evidence that was based on electrogenic measurements is not unique. However, the ability of our calculations to obtain reliable voltage changes means that we have a tool that can be used to describe a wide range of electrogenic charge transfers in channels and transporters, by combining voltage measurements with other experiments and simulations to analyze new mechanistic proposals.

• 出版日期2016-7-12