5iuk | pdb_00005iuk
Crystal structure of the DesK-DesR complex in the phosphotransfer state with high Mg2+ (150 mM)
Structural highlights
FunctionDESK_BACSU Member of the two-component regulatory system DesR/DesK, responsible for cold induction of the des gene coding for the Delta5 acyl-lipid desaturase. Acts as a sensor of the membrane fluidity. Probably activates DesR by phosphorylation.[1] [2] [3] [4] [5] Publication Abstract from PubMedTwo-component systems (TCS) are protein machineries that enable cells to respond to input signals. Histidine kinases (HK) are the sensory component, transferring information toward downstream response regulators (RR). HKs transfer phosphoryl groups to their specific RRs, but also dephosphorylate them, overall ensuring proper signaling. The mechanisms by which HKs discriminate between such disparate directions, are yet unknown. We now disclose crystal structures of the HK:RR complex DesK:DesR from Bacillus subtilis, comprising snapshots of the phosphotransfer and the dephosphorylation reactions. The HK dictates the reactional outcome through conformational rearrangements that include the reactive histidine. The phosphotransfer center is asymmetric, poised for dissociative nucleophilic substitution. The structural bases of HK phosphatase/phosphotransferase control are uncovered, and the unexpected discovery of a dissociative reactional center, sheds light on the evolution of TCS phosphotransfer reversibility. Our findings should be applicable to a broad range of signaling systems and instrumental in synthetic TCS rewiring. Regulation of signaling directionality revealed by 3D snapshots of a kinase:regulator complex in action.,Trajtenberg F, Imelio JA, Machado MR, Larrieux N, Marti MA, Obal G, Mechaly AE, Buschiazzo A Elife. 2016 Dec 12;5. pii: e21422. doi: 10.7554/eLife.21422. PMID:27938660[6] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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