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.
Article and author information
Author details
Reviewing Editor
- Michael A Marletta, University of California, Berkeley, United States
Version history
- Received: May 28, 2015
- Accepted: November 12, 2015
- Accepted Manuscript published: December 19, 2015 (version 1)
- Accepted Manuscript updated: December 23, 2015 (version 2)
- Version of Record published: February 4, 2016 (version 3)
Copyright
© 2015, McGrath et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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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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