5N2N

Crystal structure of the receiver domain of the histidine kinase CKI1 from Arabidopsis thaliana complexed with Mg2+ and BeF3-

Summary for 5N2N

• Entry DOI: 10.2210/pdb5n2n/pdb
• Related: 3MM4 3MMN 5LNM 5LNN
• Descriptor: Histidine kinase CKI1, MAGNESIUM ION, BERYLLIUM TRIFLUORIDE ION, ... (4 entities in total)
• Functional Keywords: receiver domain, histidine kinase cki1, (alpha/beta)5 fold, transferase
• Biological source: Arabidopsis thaliana (thale cress)
• Cellular location: Cell membrane ; Multi-pass membrane protein : O22267
• Total number of polymer chains: 1
• Total formula weight: 23316.19

Authors

Otrusinova, O.,Demo, G.,Padrta, P.,Jasenakova, Z.,Pekarova, B.,Gelova, Z.,Szmitkowska, A.,Kaderavek, P.,Jansen, S.,Zachrdla, M.,Klumpler, T.,Marek, J.,Hritz, J.,Janda, L.,Iwai, H.,Wimmerova, M.,Hejatko, J.,Zidek, L. (deposition date: 2017-02-08, release date: 2017-09-13, Last modification date: 2024-01-17)

Primary citation

Otrusinova, O.,Demo, G.,Padrta, P.,Jasenakova, Z.,Pekarova, B.,Gelova, Z.,Szmitkowska, A.,Kaderavek, P.,Jansen, S.,Zachrdla, M.,Klumpler, T.,Marek, J.,Hritz, J.,Janda, L.,Iwai, H.,Wimmerova, M.,Hejatko, J.,Zidek, L.
Conformational dynamics are a key factor in signaling mediated by the receiver domain of a sensor histidine kinase from Arabidopsis thaliana.
J. Biol. Chem., 292:17525-17540, 2017

PubMed Abstract: Multistep phosphorelay (MSP) cascades mediate responses to a wide spectrum of stimuli, including plant hormonal signaling, but several aspects of MSP await elucidation. Here, we provide first insight into the key step of MSP-mediated phosphotransfer in a eukaryotic system, the phosphorylation of the receiver domain of the histidine kinase CYTOKININ-INDEPENDENT 1 (CKI1) from We observed that the crystal structures of free, Mg-bound, and beryllofluoridated CKI1 (a stable analogue of the labile phosphorylated form) were identical and similar to the active state of receiver domains of bacterial response regulators. However, the three CKI1 variants exhibited different conformational dynamics in solution. NMR studies revealed that Mg binding and beryllofluoridation alter the conformational equilibrium of the β3-α3 loop close to the phosphorylation site. Mutations that perturbed the conformational behavior of the β3-α3 loop while keeping the active-site aspartate intact resulted in suppression of CKI1 function. Mechanistically, homology modeling indicated that the β3-α3 loop directly interacts with the ATP-binding site of the CKI1 histidine kinase domain. The functional relevance of the conformational dynamics observed in the β3-α3 loop of CKI1 was supported by a comparison with another histidine kinase, ETR1. In contrast to the highly dynamic β3-α3 loop of CKI1, the corresponding loop of the ETR1 receiver domain (ETR1) exhibited little conformational exchange and adopted a different orientation in crystals. Biochemical data indicated that ETR1 is involved in phosphorylation-independent signaling, implying a direct link between conformational behavior and the ability of eukaryotic receiver domains to participate in MSP.

PubMed: 28860196
DOI: 10.1074/jbc.M117.790212

Experimental method

X-RAY DIFFRACTION (2.05 Å)