IMI thanks Queen Mary University of London for a graduate teaching studentship. LW thanks the China Scholarship Council (CSC) and Queen Mary University of London for financial support. SP held a Leverhulme Trust early-career post-doctoral research fellowship. JN is grateful for the continued support of the JST CREST Grant Number JPMJCR13M4, Japan. JFA acknowledges the support of research grant F/07 476/AQ and fellowship EM-2015-068 of the Leverhulme Trust

A Marina

AE Mechaly

AJ Lomant

AM Bilwes

AM Stock

C Wang

D Georgellis

DE Koshland

DQ Duanmu

G Tang

I Kobayashi

IM Ibrahim

Iskander M. Ibrahim

J Sambrook

J Schultz

JF Allen

JM Skerker

John F. Allen

Jon Nield

LC Wang

Liang Wang

LR Swem

M Heel van

M Wojnowska

MG Surette

MK Ashby

MP Bhate

NC Rockwell

Norbert Krauß

P Scheerer

PD Scheu

PS Filippou

R Heermann

R Malpica

RS Gupta

S Kacprzak

S Nagano

S Noack

S Puthiyaveetil

SF Altschul

SJ Cai

SQ Pan

Sujith Puthiyaveetil

UK Laemmli

Y Hirose

PROTOPLASMA

English

Two-component signal transduction systems (TCSs) consist of sensor histidine kinases and response regulators. TCSs mediate adaptation to environmental changes in bacteria, plants, fungi and protists. Histidine kinase 2 (Hik2) is a sensor histidine kinase found in all known cyanobacteria and as chloroplast sensor kinase in eukaryotic algae and plants. Sodium ions have been shown to inhibit the autophosphorylation activity of Hik2 with precedes phosphoryl transfer to response regulators, but the mechanism of inhibition has not been determined. We report on the mechanism of Hik2 activation and inactivation probed by chemical cross-linking and size exclusion chromatography together with direct visualisation of the kinase using negative-stain transmission electron microscopy of single particles. We show that the functional form of Hik2 is a higher-order oligomer such as a hexamer or octamer. Increased NaCl concentration converts the active hexamer into an inactive tetramer. The action of NaCl appears to be confined to the Hik2 kinase domain

Allen, J

Ibrahim, IM

Wang, L

Puthiyaveetil, S

Krauß, N

Nield, J

UCL Discovery

Oligomeric states in sodium ion-dependent regulation of cyanobacterial histidine kinase-2

Crossref

Two-component signal transduction systems (TCSs) consist of sensor histidine kinases and response regulators. TCSs mediate adaptation to environmental changes in bacteria, plants, fungi and protists. Histidine kinase 2 (Hik2) is a sensor histidine kinase found in all known cyanobacteria and as chloroplast sensor kinase in eukaryotic algae and plants. Sodium ions have been shown to inhibit the autophosphorylation activity of Hik2 that precedes phosphoryl transfer to response regulators, but the mechanism of inhibition has not been determined. We report on the mechanism of Hik2 activation and inactivation probed by chemical cross-linking and size exclusion chromatography together with direct visualisation of the kinase using negative-stain transmission electron microscopy of single particles. We show that the functional form of Hik2 is a higher-order oligomer such as a hexamer or octamer. Increased NaCl concentration converts the active hexamer into an inactive tetramer. The action of NaCl appears to be confined to the Hik2 kinase domain

Ibrahim, Iskander M

Wang, Liang

Puthiyaveetil, Sujith

Krauss, Norbert

Nield, Jon

Allen, John F

Spiral - Imperial College Digital Repository

Ibrahim, Iskander M.

Krauß, Norbert

Allen, John F.

Repository KITopen

Two-component signal transduction systems (TCSs) consist of sensor histidine kinases and response regulators. TCSs mediate adaptation to environmental changes in bacteria, plants, fungi, and protists. Histidine kinase 2 (Hik2) is a sensor histidine kinase found in all known cyanobacteria and as chloroplast sensor kinase in eukaryotic algae and plants. Sodium ions have been shown to inhibit the autophosphorylation activity of Hik2 that precedes phosphoryl transfer to response regulators, but the mechanism of inhibition has not been determined. We report on the mechanism of Hik2 activation and inactivation probed by chemical crosslinking and size exclusion chromatography together with direct visualisation of the kinase using negative-stain transmission electron microscopy of single particles. We show that the functional form of Hik2 is a higher order oligomer such as a hexamer or octamer. Increased NaCl concentration converts the active hexamer into an inactive tetramer. Furthermore, the action of NaCl appears to be confined to the Hik2 kinase domain

Oligomeric States In Sodium Ion-Dependent Regulation Of Cyanobacterial Histidine Kinase-2

ABSTRACTTwo-component signal transduction systems (TCSs) consist of sensor histidine kinases and response regulators. TCSs mediate adaptation to environmental changes in bacteria, plants, fungi, and protists. Histidine kinase 2 (Hik2) is a sensor histidine kinase found in all known cyanobacteria and as chloroplast sensor kinase in eukaryotic algae and plants. Sodium ions have been shown to inhibit the autophosphorylation activity of Hik2 that precedes phosphoryl transfer to response regulators, but the mechanism of inhibition has not been determined. We report on the mechanism of Hik2 activation and inactivation probed by chemical crosslinking and size exclusion chromatography together with direct visualisation of the kinase using negative-stain transmission electron microscopy of single particles. We show that the functional form of Hik2 is a higher order oligomer such as a hexamer or octamer. Increased NaCl concentration converts the active hexamer into an inactive tetramer. Furthermore, the action of NaCl appears to be confined to the Hik2 kinase domain.IMPORTANCEBacteria sense change and respond to it by means of two-component regulatory systems. The sensor component is a protein that becomes covalently modified by a phosphate group on a histidine side chain. The response regulator accepts the phosphate group onto an aspartate, with structural and functional consequences, often for gene transcription. Histidine kinase 2 is a sensor of sodium ion concentration and redox potential, regulating transcription of genes for light-harvesting and reaction center proteins of photosynthesis in cyanobacteria and chloroplasts of algae and plants. Using radiolabeling, chemical crosslinking, chromatography and electron microscopy, we find that sodium ion concentration governs the oligomeric state of Histidine Kinase 2 and its phosphorylation by ATP.</jats:sec

Oligomeric states in sodium ion–dependent regulation of cyanobacterial histidine kinase-2

KITopen

Krauss, N

Allen, JF

Queen Mary Research Online

https://qmro.qmul.ac.uk/xmlui/bitstream/123456789/31400/1/Nield%20Oligomeric%20states%20in%20sodium%202017%20Published.pdf

Oligomeric states in sodium ion-dependent regulation of cyanobacterial histidine kinase-2

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UCL Discovery

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Spiral - Imperial College Digital Repository

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UCL Discovery

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KITopen

Queen Mary Research Online