1Institut de Pharmacologie et de Biologie Structural CNRS, UPR9062, 205 route de Narbonne, 31077 Toulouse, France.
2These authors made equal contribution to this work.
3email: samama@ipbs.fr
Bacterial adaptation to the environment is accomplished through the coordinated activation of specific sensory receptors and signal processing proteins. Among the best characterized of these pathways are those which employ the two-component paradigm. In these systems, signal transmission is mediated by Mg2+-dependent phospho-relay reactions between histidine auto-kinases and phosphoaccepting receiver domains in response-regulator proteins. Although this mechanism of activation is common to all response-regulators, detrimental cross-talk between different two-component pathways within the same cell is minimized through the use of specific recognition domains. Here, we report the crystal structure, at 2.95 Å resolution, of the response regulator of bacterial chemotaxis, CheY, bound to the recognition domain from its cognate histidine kinase, CheA. The structure suggests that molecular recognition, in this low affinity complex (KD = 2 M), may also contribute to the mechanism of CheY activation.
M), may also contribute to the mechanism of CheY activation.
