title: Probing the nucleotide-binding activity of a redox sensor: two-component regulatory control in chloroplasts.
abstract: Two-component signal transduction systems mediate adaptation to environmental changes in bacteria, plants, fungi, and protists. Each two-component system consists of a sensor histidine kinase and a response regulator. Chloroplast sensor kinase (CSK) is a modified sensor histidine kinase found in chloroplasts-photosynthetic organelles of plants and algae. CSK regulates the transcription of chloroplast genes in response to changes in photosynthetic electron transport. In this study, the full-length and truncated forms of Arabidopsis CSK proteins were overexpressed and purified in order to characterise their kinase and redox sensing activities. Our results show that CSK contains a modified kinase catalytic domain that binds ATP with high affinity and forms a quinone adduct that may confer redox sensing activity.
authors.affiliation: Faculty of Engineering and Science, University of Greenwich, Chatham Maritime, Kent, UK.
authors.forename: Iskander M
authors.initials: IM
authors.lastname: Ibrahim
authors.affiliation: Institute of Biological Chemistry, Washington State University, Pullman, WA, USA.
authors.forename: Sujith
authors.initials: S
authors.lastname: Puthiyaveetil
authors.affiliation: 12 Ballamaddrell, Port Erin, Isle of Man, UK.
authors.forename: Christine
authors.initials: C
authors.lastname: Khan
authors.affiliation: Research Department of Genetics, Evolution and Environment, University College London, Darwin Building, Gower Street, London, WC1E 6BT, UK. j.f.allen@ucl.ac.uk.
authors.forename: John F
authors.identifier: http://orcid.org/0000-0002-0950-0429
authors.initials: JF
authors.lastname: Allen
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D002736:Chloroplasts / Q000235:genetics / Q000378:metabolism*; D000071677:Histidine Kinase / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D010084:Oxidation-Reduction; D010766:Phosphorylation; D010788:Photosynthesis; D011994:Recombinant Proteins; D016415:Sequence Alignment; D015398:Signal Transduction
chemical_list: D029681:Arabidopsis Proteins; D011994:Recombinant Proteins; D000255:Adenosine Triphosphate; D000071677:Histidine Kinase; C000615593:chloroplast sensor kinase, Arabidopsis
keywords: Chloroplast DNA; Chloroplast sensor kinase; Cyanobacteria; Photosystem stoichiometry; Plastoquinone; Redox regulation; Response regulator; Sensor histidine kinase; Transcription; Two-component regulatory system