Title
The RavA-ViaA Chaperone-Like System Interacts with and Modulates the Activity of the Fumarate Reductase Respiratory Complex
Author
Keith S. Wong, Vaibhav Bhandari, Sarath C. Janga, Walid A. Houry
Year
2016
Journal
Journal of Molecular Biology
Abstract
RavA is a MoxR AAA + protein that functions together with a partner protein that we termed ViaA containing a von Willebrand Factor A (VWA) domain. However, the functional role of RavA-ViaA in the cell is not yet well-established. Here, we show that RavA-ViaA are functionally associated with anaerobic respiration in Escherichia coli through interactions with the fumarate reductase (Frd) electron transport complex. Expression analysis of ravA and viaA genes showed that both proteins are co-expressed with multiple anaerobic respiratory genes, many of which are regulated by the anaerobic transcriptional regulator Fnr. Consistently, the expression of both ravA and viaA was found to be dependent on Fnr in cells grown under oxygen-limiting condition. ViaA was found to physically interact with FrdA; the flavin-containing subunit of the Frd complex. Both RavA and the Fe-S-containing subunit of the Frd complex, FrdB, regulate this interaction. Importantly, Frd activity was observed to increase in the absence of RavA and ViaA. This indicates that RavA and ViaA modulate the activity of the Frd complex, signifying a potential regulatory chaperone-like function for RavA-ViaA during bacterial anaerobic respiration with fumarate as the terminal electron acceptor.
Instrument
J-810
Keywords
Circular dichroism, Secondary structure, Thermal stability, Thermodynamics, Biochemistry