Structural basis of interprotein electron transfer in bacterial sulfite oxidation
- University of California, San Diego, United States
- The Victor Chang Cardiac Research Institute, Australia
- La Trobe University, Australia
- University of Sydney, Australia
- University of Queensland, Australia
Abstract
Interprotein electron transfer underpins the essential processes of life and relies on the formation of specific, yet transient protein-protein interactions. In biological systems, the detoxification of sulfite is catalyzed by the sulfite-oxidizing enzymes (SOEs), which interact with an electron acceptor for catalytic turnover. Here, we report the structural and functional analyses of the SOE SorT from Sinorhizobium meliloti and its cognate electron acceptor SorU. Kinetic and thermodynamic analyses of the SorT/SorU interaction showed the complex is dynamic in solution, and that the proteins interact with Kd = 13.5 {plus minus} 0.8 βM. The crystal structures of the oxidized SorT and SorU both in isolation and in complex, reveal the interface to be remarkably electrostatic, with an unusually large number of direct hydrogen bonding interactions. The assembly of the complex is accompanied by an adjustment in the structure of SorU and conformational sampling provides a mechanism for dissociation of the SorT/SorU assembly.
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© 2015, McGrath et al.
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Structural basis of interprotein electron transfer in bacterial sulfite oxidation
eLife 4:e09066.
https://doi.org/10.7554/eLife.09066
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