1sr2
Solution structure of the Escherichia coli YojN Histidine-Phosphotransferase (HPt) domain
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OverviewOverview
The Rcs signaling system in Escherichia coli controls a variety of, physiological functions, including capsule synthesis, cell division and, motility. The activity of the central regulator RcsB is modulated by, phosphorylation through the sensor kinases YojN and RcsC, with the YojN, histidine phosphotransferase (HPt) domain representing the catalytic unit, that coordinates the potentially reversible phosphotransfer reaction, between the receiver domains of the RcsB and RcsC proteins. Heteronuclear, high-resolution NMR spectroscopy was employed to determine the solution, structure of the YojN-HPt domain and to map the interaction with its two, cognate receiver domains. The solution structure of YojN-HPt exhibits a, well-ordered and rigid protein core consisting of the five helices alphaI, to alphaV. The helices alphaII to alphaV form a four-helix bundle, signature motif common to proteins of similar function, and helix alphaI, forms a cap on top of the bundle. The helix alphaII is separated by a, proline induced kink into two parts with different orientations and, dynamic behavior that is potentially important for complex formation with, other proteins. The N-terminal part of YojN-HPt spanning the first 26, amino acid residues seems to contain neither a regular secondary structure, nor a stable tertiary structure and is disordered in solution. The, identified YojN-HPt recognition sites for the regulator RcsB and for the, isolated receiver domain of the RcsC kinase largely overlap in defined, regions of the helices alphaII and alphaIII, but show significant, differences. Using the residues with the largest chemical shift changes, obtained from titration experiments, we observed a dissociation constant, of approximately 200microM for YojN-HPt/RcsC-PR and of 40microM for, YojN-HPt/RcsB complexes. Our data indicate the presence of a recognition, area in close vicinity to the active-site histidine residue of HPt domains, as a determinant of specificity in signal-transduction pathways.
About this StructureAbout this Structure
1SR2 is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
ReferenceReference
Solution structure of the Escherichia coli YojN histidine-phosphotransferase domain and its interaction with cognate phosphoryl receiver domains., Rogov VV, Bernhard F, Lohr F, Dotsch V, J Mol Biol. 2004 Oct 29;343(4):1035-48. PMID:15476819
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