Abstract
Archaea are motile by the rotation of the archaellum. The archaellum switches between clockwise and counterclockwise rotation, and movement along a chemical gradient is possible by modulation of the switching frequency. This modulation involves the response regulator CheY and the archaellum adaptor protein CheF. In this study, two new crystal forms and protein structures of CheY are reported. In both crystal forms, CheY is arranged in a domain-swapped conformation. CheF, the protein bridging the chemotaxis signal transduction system and the motility apparatus, was recombinantly expressed, purified and subjected to X-ray data collection.
Highlights
Archaea and bacteria share the ability to move in response to chemical or physical stimuli towards favorable growth conditions (Marwan & Oesterhelt, 2000; Quax, Albers et al, 2018)
The molecular basis underlying taxis is composed of two systems: chemotaxis signal transduction, which processes the external stimulus, and the flagellum/archaellum, which responds to the chemotaxis output signal
Proteins from H. salinarum have been expressed recombinantly in E. coli, but primarily as unfolded proteins that rely on the uncertainty of refolding protocols (Marg et al, 2005; Grininger et al, 2006)
Summary
Archaea and bacteria share the ability to move in response to chemical or physical stimuli towards favorable growth conditions (Marwan & Oesterhelt, 2000; Quax, Albers et al, 2018). Motility is based on the rotation of the flagellum (in bacteria) and the archaellum (in archaea; formerly known as the archaeal flagellum), respectively, and the directionality of the movement is provided by modulating the switching frequency in response to the stimulus (Armitage, 1999). The overall mechanism of chemotaxis is conserved in archaea and bacteria (Szurmant & Ordal, 2004). Generally known as methyl-accepting chemotaxis proteins (MCPs) and referred to as halobacterial transducer proteins (Htrs) in halophilic archaea (Zhang et al, 1996), sense external stimuli such as chemicals, oxygen or light.
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