6RH2

Revisiting pH-gated conformational switch. Complex HK853-RR468 D53A pH 5.3

Summary for 6RH2

• Entry DOI: 10.2210/pdb6rh2/pdb
• Descriptor: Sensor histidine kinase, Response regulator, ADENOSINE-5'-DIPHOSPHATE, ... (5 entities in total)
• Functional Keywords: histidine kinase, response regulator, phosphotransfer, phosphatase, signaling protein
• Biological source: Thermotoga maritima; More
• Total number of polymer chains: 4
• Total formula weight: 88372.21

Authors

Mideros-Mora, C.,Casino, P.,Marina, A. (deposition date: 2019-04-18, release date: 2020-02-19, Last modification date: 2024-01-24)

Primary citation

Mideros-Mora, C.,Miguel-Romero, L.,Felipe-Ruiz, A.,Casino, P.,Marina, A.
Revisiting the pH-gated conformational switch on the activities of HisKA-family histidine kinases.
Nat Commun, 11:769-769, 2020

PubMed Abstract: Histidine is a versatile residue playing key roles in enzyme catalysis thanks to the chemistry of its imidazole group that can serve as nucleophile, general acid or base depending on its protonation state. In bacteria, signal transduction relies on two-component systems (TCS) which comprise a sensor histidine kinase (HK) containing a phosphorylatable catalytic His with phosphotransfer and phosphatase activities over an effector response regulator. Recently, a pH-gated model has been postulated to regulate the phosphatase activity of HisKA HKs based on the pH-dependent rotamer switch of the phosphorylatable His. Here, we have revisited this model from a structural and functional perspective on HK853-RR468 and EnvZ-OmpR TCS, the prototypical HisKA HKs. We have found that the rotamer of His is not influenced by the environmental pH, ruling out a pH-gated model and confirming that the chemistry of the His is responsible for the decrease in the phosphatase activity at acidic pH.

PubMed: 32034139
DOI: 10.1038/s41467-020-14540-5

Experimental method

X-RAY DIFFRACTION (2 Å)