Article

A new structural domain in the Escherichia coli RcsC hybrid sensor kinase connects histidine kinase and phosphoreceiver domains.

Institute of Biophysical Chemistry, Centre for Biomolecular Magnetic Resonance, JW Goethe-University, Frankfurt-am-Main, Germany.
Journal of Molecular Biology (impact factor: 4). 12/2006; 364(1):68-79. DOI:10.1016/j.jmb.2006.07.052
Source: PubMed

ABSTRACT The Rcs signalling pathway controls a variety of physiological functions like capsule synthesis, cell division or motility in prokaryotes. The Rcs regulation cascade, involving a multi-step phosphorelay between the two membrane-bound hybrid sensor kinases RcsC and RcsD and the global regulator RcsB, is, up to now, one of the most complicated regulatory systems in bacteria. To understand the structural basis of Rcs signal transduction, NMR spectroscopy was employed to determine the solution structure of the RcsC C terminus, possessing a phosphoreceiver domain (RcsC-PR), and a region previously described as a long linker between the histidine kinase domain of RcsC (RcsC-HK) and the RcsC-PR. We have found that the linker region comprises an independent structural domain of a new alpha/beta organization, which we named RcsC-ABL domain (Alpha/Beta/Loop). The ABL domain appears to be a conserved and unique structural element of RcsC-like kinases with no significant sequence homology to other proteins. The second domain of the C terminus, the RcsC-PR domain, represents a well-folded CheY-like phosphoreceiver domain with the central parallel beta-sheet covered with two alpha-helical layers on both sides. We have mapped the interaction of RcsC-ABL and RcsC-PR with the histidine phosphotransfer domain (HPt) of RcsD. In addition we have characterized the interaction with and the conformational effects of Mg2+ and the phosphorylation mimetic BeF(-)(3) on RcsC-ABL and RcsC-PR.

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  • Article: A disulfide bridge network within the soluble periplasmic domain determines structure and function of the outer membrane protein RCSF.
    Vladimir V Rogov, Natalia Yu Rogova, Frank Bernhard, Frank Löhr, Volker Dötsch
    [show abstract] [hide abstract]
    ABSTRACT: RcsF, a proposed auxiliary regulator of the regulation of capsule synthesis (rcs) phosphorelay system, is a key element for understanding the RcsC-D-A/B signaling cascade, which is responsible for the regulation of more than 100 genes and is involved in cell division, motility, biofilm formation, and virulence. The RcsC-D-A/B system is one of the most complex bacterial signal transduction pathways, consisting of several membrane-bound and soluble proteins. RcsF is a lipoprotein attached to the outer membrane and plays an important role in activating the RcsC-d-A/B pathway. The exact mechanism of activation of the rcs phosphorelay by RcsF, however, remains unknown. We have analyzed the sequence of RcsF and identified three structural elements: 1) an N-terminal membrane-anchored helix (residues 3-13), 2) a loop (residues 14-48), and 3) a C-terminal folded domain (residues 49-134). We have determined the structure of this C-terminal domain and started to investigate its interaction with potential partners. Important features of its structure are two disulfide bridges between Cys-74 and Cys-118 and between Cys-109 and Cys-124. To evaluate the importance of this RcsF disulfide bridge network in vivo, we have examined the ability of the full-length protein and of specific Cys mutants to initiate the rcs signaling cascade. The results indicate that the Cys-74/Cys-118 and the Cys-109/Cys-124 residues correlate pairwise with the activity of RcsF. Interaction studies showed a weak interaction with an RNA hairpin. However, no interaction could be detected with reagents that are believed to activate the rcs phosphorelay, such as lysozyme, glucose, or Zn(2+) ions.
    Journal of Biological Chemistry 04/2011; 286(21):18775-83. · 4.77 Impact Factor
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.

Keywords

central parallel beta-sheet
 
complicated regulatory systems
 
conformational effects
 
global regulator RcsB
 
histidine phosphotransfer domain
 
independent structural domain
 
linker region
 
phosphorylation mimetic BeF(-)(3)
 
Rcs regulation cascade
 
Rcs signal transduction
 
Rcs signalling pathway controls
 
RcsC C terminus
 
RcsC-ABL domain
 
RcsC-HK
 
RcsC-like kinases
 
RcsC-PR
 
RcsC-PR domain
 
two membrane-bound hybrid sensor kinases RcsC
 
unique structural element
 
well-folded CheY-like phosphoreceiver domain