3MMN

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

Summary for 3MMN

• Entry DOI: 10.2210/pdb3mmn/pdb
• Descriptor: Histidine kinase homolog, MAGNESIUM ION (3 entities in total)
• Functional Keywords: receiver domain, cki1, cytokinin signaling, rossmann-fold, chey-like, arabidopsis, transferase
• Biological source: Arabidopsis thaliana (mouse-ear cress,thale-cress)
• Cellular location: Cell membrane; Multi-pass membrane protein: O22267
• Total number of polymer chains: 1
• Total formula weight: 23250.18

Authors

Marek, J.,Klumpler, T.,Pekarova, B.,Triskova, O.,Horak, J.,Zidek, L.,Dopitova, R.,Hejatko, J.,Janda, L. (deposition date: 2010-04-20, release date: 2011-04-13, Last modification date: 2023-09-06)

Primary citation

Pekarova, B.,Klumpler, T.,Triskova, O.,Horak, J.,Jansen, S.,Dopitova, R.,Borkovcova, P.,Papouskova, V.,Nejedla, E.,Sklenar, V.,Marek, J.,Zidek, L.,Hejatko, J.,Janda, L.
Structure and binding specificity of the receiver domain of sensor histidine kinase CKI1 from Arabidopsis thaliana.
Plant J., 67:827-839, 2011

PubMed Abstract: Multistep phosphorelay (MSP) signaling mediates responses to a variety of important stimuli in plants. In Arabidopsis MSP, the signal is transferred from sensor histidine kinase (HK) via histidine phosphotransfer proteins (AHP1-AHP5) to nuclear response regulators. In contrast to ancestral two-component signaling in bacteria, protein interactions in plant MSP are supposed to be rather nonspecific. Here, we show that the C-terminal receiver domain of HK CKI1 (CKI1(RD) ) is responsible for the recognition of CKI1 downstream signaling partners, and specifically interacts with AHP2, AHP3 and AHP5 with different affinities. We studied the effects of Mg²⁺, the co-factor necessary for signal transduction via MSP, and phosphorylation-mimicking BeF₃⁻ on CKI1(RD) in solution, and determined the crystal structure of free CKI1(RD) and CKI1(RD) in a complex with Mg²⁺. We found that the structure of CKI1(RD) shares similarities with the only known structure of plant HK, ETR1(RD) , with the main differences being in loop L3. Magnesium binding induces the rearrangement of some residues around the active site of CKI1(RD) , as was determined by both X-ray crystallography and NMR spectroscopy. Collectively, these results provide initial insights into the nature of molecular mechanisms determining the specificity of MSP signaling and MSP catalysis in plants.

PubMed: 21569135
DOI: 10.1111/j.1365-313X.2011.04637.x

Experimental method

X-RAY DIFFRACTION (2.2 Å)