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Yadav M, Sathe J, Teronpi V, Kumar A. Navigating the signaling landscape of Ralstonia solanacearum: a study of bacterial two-component systems. World J Microbiol Biotechnol 2024; 40:153. [PMID: 38564115 DOI: 10.1007/s11274-024-03950-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Accepted: 03/10/2024] [Indexed: 04/04/2024]
Abstract
Ralstonia solanacearum, the bacterium that causes bacterial wilt, is a destructive phytopathogen that can infect over 450 different plant species. Several agriculturally significant crop plants, including eggplant, tomato, pepper, potato, and ginger, are highly susceptible to this plant disease, which has a global impact on crop quality and yield. There is currently no known preventive method that works well for bacterial wilt. Bacteria use two-component systems (TCSs) to sense their environment constantly and react appropriately. This is achieved by an extracellular sensor kinase (SK) capable of sensing a suitable signal and a cytoplasmic response regulator (RR) which gives a downstream response. Moreover, our investigation revealed that R. solanacearum GMI1000 possesses a substantial count of TCSs, specifically comprising 36 RRs and 27 SKs. While TCSs are known targets for various human pathogenic bacteria, such as Salmonella, the role of TCSs in R. solanacearum remains largely unexplored in this context. Notably, numerous inhibitors targeting TCSs have been identified, including GHL (Gyrase, Hsp, and MutL) compounds, Walk inhibitors, and anti-TCS medications like Radicicol. Consequently, the investigation into the involvement of TCSs in virulence and pathogenesis has gained traction; however, further research is imperative to ascertain whether TCSs could potentially supplant conventional anti-wilt therapies. This review delves into the prospective utilization of TCSs as an alternative anti-wilt therapy, focusing on the lethal phytopathogen R. solanacearum.
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Affiliation(s)
- Mohit Yadav
- Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, Assam, 784028, India
| | - Janhavi Sathe
- Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, Assam, 784028, India
- Institute for Stem Cell Science and Regenerative Medicine, Bangalore, Karnataka, 560065, India
| | - Valentina Teronpi
- Department of Zoology, Pandit Deendayal Upadhyaya Adarsha Mahavidyalaya, Behali, Biswanath, Assam, 784184, India
| | - Aditya Kumar
- Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, Assam, 784028, India.
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2
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Dikiy I, Swingle D, Toy K, Edupuganti UR, Rivera-Cancel G, Gardner KH. Diversity of function and higher-order structure within HWE sensor histidine kinases. J Biol Chem 2023; 299:104934. [PMID: 37331599 PMCID: PMC10359499 DOI: 10.1016/j.jbc.2023.104934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Revised: 06/09/2023] [Accepted: 06/12/2023] [Indexed: 06/20/2023] Open
Abstract
Integral to the protein structure/function paradigm, oligomeric state is typically conserved along with function across evolution. However, notable exceptions such as the hemoglobins show how evolution can alter oligomerization to enable new regulatory mechanisms. Here, we examine this linkage in histidine kinases (HKs), a large class of widely distributed prokaryotic environmental sensors. While the majority of HKs are transmembrane homodimers, members of the HWE/HisKA2 family can deviate from this architecture as exemplified by our finding of a monomeric soluble HWE/HisKA2 HK (EL346, a photosensing light-oxygen-voltage [LOV]-HK). To further explore the diversity of oligomerization states and regulation within this family, we biophysically and biochemically characterized multiple EL346 homologs and found a range of HK oligomeric states and functions. Three LOV-HK homologs are primarily dimeric with differing structural and functional responses to light, while two Per-ARNT-Sim-HKs interconvert between differentially active monomers and dimers, suggesting dimerization might control enzymatic activity for these proteins. Finally, we examined putative interfaces in a dimeric LOV-HK, finding that multiple regions contribute to dimerization. Our findings suggest the potential for novel regulatory modes and oligomeric states beyond those traditionally defined for this important family of environmental sensors.
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Affiliation(s)
- Igor Dikiy
- Structural Biology Initiative, CUNY Advanced Science Research Center, New York, New York, USA
| | - Danielle Swingle
- Structural Biology Initiative, CUNY Advanced Science Research Center, New York, New York, USA; PhD. Program in Biochemistry, The Graduate Center - City University of New York, New York, New York, USA
| | - Kaitlyn Toy
- Structural Biology Initiative, CUNY Advanced Science Research Center, New York, New York, USA; Department of Chemistry and Biochemistry, City College of New York, New York, New York, USA
| | - Uthama R Edupuganti
- Structural Biology Initiative, CUNY Advanced Science Research Center, New York, New York, USA; PhD. Program in Biochemistry, The Graduate Center - City University of New York, New York, New York, USA
| | - Giomar Rivera-Cancel
- Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Kevin H Gardner
- Structural Biology Initiative, CUNY Advanced Science Research Center, New York, New York, USA; Department of Chemistry and Biochemistry, City College of New York, New York, New York, USA; PhD. Programs in Biochemistry, Biology, and Chemistry, The Graduate Center - City University of New York, New York, New York, USA.
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3
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Boyer NR, Tokmina-Lukaszewska M, Bueno Batista M, Mus F, Dixon R, Bothner B, Peters JW. Structural insights into redox signal transduction mechanisms in the control of nitrogen fixation by the NifLA system. Proc Natl Acad Sci U S A 2023; 120:e2302732120. [PMID: 37459513 PMCID: PMC10372690 DOI: 10.1073/pnas.2302732120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 06/15/2023] [Indexed: 07/20/2023] Open
Abstract
NifL is a conformationally dynamic flavoprotein responsible for regulating the activity of the σ54-dependent activator NifA to control the transcription of nitrogen fixation (nif) genes in response to intracellular oxygen, cellular energy, or nitrogen availability. The NifL-NifA two-component system is the master regulatory system for nitrogen fixation. NifL serves as a sensory protein, undergoing signal-dependent conformational changes that modulate its interaction with NifA, forming the NifL-NifA complex, which inhibits NifA activity in conditions unsuitable for nitrogen fixation. While NifL-NifA regulation is well understood, these conformationally flexible proteins have eluded previous attempts at structure determination. In work described here, we advance a structural model of the NifL dimer supported by a combination of scattering techniques and mass spectrometry (MS)-coupled structural analyses that report on the average structure in solution. Using a combination of small angle X-ray scattering-derived electron density maps and MS-coupled surface labeling, we investigate the conformational dynamics responsible for NifL oxygen and energy responses. Our results reveal conformational differences in the structure of NifL under reduced and oxidized conditions that provide the basis for a model for modulating NifLA complex formation in the regulation of nitrogen fixation in response to oxygen in the model diazotroph, Azotobacter vinelandii.
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Affiliation(s)
- Nathaniel R. Boyer
- Institute of Biological Chemistry, Washington State University, Pullman, WA99164
| | | | - Marcelo Bueno Batista
- Department of Molecular Microbiology, John Innes Centre, NorwichNR4 7UH, United Kingdom
| | - Florence Mus
- Institute of Biological Chemistry, Washington State University, Pullman, WA99164
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK73019
| | - Ray Dixon
- Department of Molecular Microbiology, John Innes Centre, NorwichNR4 7UH, United Kingdom
| | - Brian Bothner
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT59717
| | - John W. Peters
- Institute of Biological Chemistry, Washington State University, Pullman, WA99164
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK73019
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4
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Kumarapperuma I, Tom IP, Bandara S, Montano S, Yang X. Mode of autophosphorylation in bacteriophytochromes RpBphP2 and RpBphP3. Photochem Photobiol Sci 2023; 22:1257-1266. [PMID: 36757561 PMCID: PMC10619329 DOI: 10.1007/s43630-023-00366-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 01/12/2023] [Indexed: 02/10/2023]
Abstract
Phytochromes are red-light photoreceptors that regulate a wide range of physiological processes in plants, fungi and bacteria. Canonical bacteriophytochromes are photosensory histidine kinases that undergo light-dependent autophosphorylation, thereby regulating cellular responses to red light via two-component signaling pathways. However, the molecular mechanism of kinase activation remains elusive for bacteriophytochromes. In particular, the directionality of autophosphorylation is still an open question in these dimeric photoreceptor kinases. In this work, we perform histidine kinase assays on two tandem bacteriophytochromes RpBphP2 and RpBphP3 from the photosynthetic bacterium Rhodopseudomonas palustris. By examining the kinase activities of full-length bacteriophytochromes and two loss-of-function mutants under different light conditions, we demonstrate that RpBphP2 and RpBphP3 undergo light-dependent trans-phosphorylation between protomers in both homodimeric and heterodimeric forms. We have further determined the crystal structure of the histidine kinase domains of RpBphP2 at 3.19 Å resolution. Based on structural comparisons and homology modeling, we also present a model to account for the actions of trans-autophosphorylation in bacteriophytochromes.
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Affiliation(s)
| | - Irin P Tom
- Department of Chemistry, University of Illinois Chicago, Chicago, IL, USA
| | - Sepalika Bandara
- Department of Chemistry, University of Illinois Chicago, Chicago, IL, USA
| | - Sherwin Montano
- Department of Chemistry, University of Illinois Chicago, Chicago, IL, USA
| | - Xiaojing Yang
- Department of Chemistry, University of Illinois Chicago, Chicago, IL, USA.
- Department of Ophthalmology and Vision Sciences, University of Illinois Chicago, Chicago, IL, USA.
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5
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Wahlgren WY, Claesson E, Tuure I, Trillo-Muyo S, Bódizs S, Ihalainen JA, Takala H, Westenhoff S. Structural mechanism of signal transduction in a phytochrome histidine kinase. Nat Commun 2022; 13:7673. [PMID: 36509762 PMCID: PMC9744887 DOI: 10.1038/s41467-022-34893-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 11/10/2022] [Indexed: 12/14/2022] Open
Abstract
Phytochrome proteins detect red/far-red light to guide the growth, motion, development and reproduction in plants, fungi, and bacteria. Bacterial phytochromes commonly function as an entrance signal in two-component sensory systems. Despite the availability of three-dimensional structures of phytochromes and other two-component proteins, the conformational changes, which lead to activation of the protein, are not understood. We reveal cryo electron microscopy structures of the complete phytochrome from Deinoccocus radiodurans in its resting and photoactivated states at 3.6 Å and 3.5 Å resolution, respectively. Upon photoactivation, the photosensory core module hardly changes its tertiary domain arrangement, but the connector helices between the photosensory and the histidine kinase modules open up like a zipper, causing asymmetry and disorder in the effector domains. The structures provide a framework for atom-scale understanding of signaling in phytochromes, visualize allosteric communication over several nanometers, and suggest that disorder in the dimeric arrangement of the effector domains is important for phosphatase activity in a two-component system. The results have implications for the development of optogenetic applications.
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Affiliation(s)
- Weixiao Yuan Wahlgren
- grid.8761.80000 0000 9919 9582Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Elin Claesson
- grid.8761.80000 0000 9919 9582Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Iida Tuure
- grid.9681.60000 0001 1013 7965Department of Biological and Environmental Science, Nanoscience Center, University of Jyvaskyla, Jyvaskyla, Finland
| | - Sergio Trillo-Muyo
- grid.8761.80000 0000 9919 9582Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg, Sweden
| | - Szabolcs Bódizs
- grid.8761.80000 0000 9919 9582Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Janne A. Ihalainen
- grid.9681.60000 0001 1013 7965Department of Biological and Environmental Science, Nanoscience Center, University of Jyvaskyla, Jyvaskyla, Finland
| | - Heikki Takala
- grid.9681.60000 0001 1013 7965Department of Biological and Environmental Science, Nanoscience Center, University of Jyvaskyla, Jyvaskyla, Finland ,grid.7737.40000 0004 0410 2071Faculty of Medicine, Anatomy, University of Helsinki, Helsinki, Finland
| | - Sebastian Westenhoff
- grid.8761.80000 0000 9919 9582Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden ,grid.8993.b0000 0004 1936 9457Department of Chemistry—BMC, Biochemistry, Uppsala University, Uppsala, Sweden
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6
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Ataeian M, Vadlamani A, Haines M, Mosier D, Dong X, Kleiner M, Strous M, Hawley AK. Proteome and strain analysis of cyanobacterium Candidatus "Phormidium alkaliphilum" reveals traits for success in biotechnology. iScience 2021; 24:103405. [PMID: 34877483 PMCID: PMC8633866 DOI: 10.1016/j.isci.2021.103405] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 08/27/2021] [Accepted: 11/03/2021] [Indexed: 11/18/2022] Open
Abstract
Cyanobacteria encompass a diverse group of photoautotrophic bacteria with important roles in nature and biotechnology. Here we characterized Candidatus “Phormidium alkaliphilum,” an abundant member in alkaline soda lake microbial communities globally. The complete, circular whole-genome sequence of Ca. “P. alkaliphilum” was obtained using combined Nanopore and Illumina sequencing of a Ca. “P. alkaliphilum” consortium. Strain-level diversity of Ca. “P. alkaliphilum” was shown to contribute to photobioreactor robustness under different operational conditions. Comparative genomics of closely related species showed that adaptation to high pH was not attributed to specific genes. Proteomics at high and low pH showed only minimal changes in gene expression, but higher productivity in high pH. Diverse photosystem antennae proteins, and high-affinity terminal oxidase, compared with other soda lake cyanobacteria, appear to contribute to the success of Ca. “P. alkaliphilum” in photobioreactors and biotechnology applications. Closed genome of the cyanobacteria Ca. P. alkaliphilum from high-pH photobioreactor Genetic factors lead this Phormidium to outcompete other cyanobacteria in photobioreactor Adaptation to high pH and alkalinity is not linked to specific genes Strain-level diversity contributes Ca. P. alkaliphilum success in changing conditions
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Affiliation(s)
- Maryam Ataeian
- Department of Geoscience, University of Calgary, Calgary, AB, Canada
| | | | - Marianne Haines
- Department of Geoscience, University of Calgary, Calgary, AB, Canada
| | - Damon Mosier
- Department of Geoscience, University of Calgary, Calgary, AB, Canada
| | - Xiaoli Dong
- Department of Geoscience, University of Calgary, Calgary, AB, Canada
| | - Manuel Kleiner
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA
| | - Marc Strous
- Department of Geoscience, University of Calgary, Calgary, AB, Canada
| | - Alyse K. Hawley
- Department of Geoscience, University of Calgary, Calgary, AB, Canada
- School of Engineering, University of British Columbia Okanagan, Kelowna, BC, Canada
- Corresponding author
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7
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Hadi J, Wu S, Soni A, Gardner A, Brightwell G. Genetic Factors Affect the Survival and Behaviors of Selected Bacteria during Antimicrobial Blue Light Treatment. Int J Mol Sci 2021; 22:10452. [PMID: 34638788 DOI: 10.3390/ijms221910452] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 09/22/2021] [Accepted: 09/24/2021] [Indexed: 12/26/2022] Open
Abstract
Antimicrobial resistance is a global, mounting and dynamic issue that poses an immediate threat to human, animal, and environmental health. Among the alternative antimicrobial treatments proposed to reduce the external use of antibiotics is electromagnetic radiation, such as blue light. The prevailing mechanistic model is that blue light can be absorbed by endogenous porphyrins within the bacterial cell, inducing the production of reactive oxygen species, which subsequently inflict oxidative damages upon different cellular components. Nevertheless, it is unclear whether other mechanisms are involved, particularly those that can affect the efficacy of antimicrobial blue light treatments. In this review, we summarize evidence of inherent factors that may confer protection to a selected group of bacteria against blue light-induced oxidative damages or modulate the physiological characteristics of the treated bacteria, such as virulence and motility. These include descriptions of three major photoreceptors in bacteria, chemoreceptors, SOS-dependent DNA repair and non-SOS protective mechanisms. Future directions are also provided to assist with research efforts to increase the efficacy of antimicrobial blue light and to minimize the development of blue light-tolerant phenotypes.
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8
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Jiao S, DeStefano A, Monroe JI, Barry M, Sherck N, Casey T, Segalman RA, Han S, Shell MS. Quantifying Polypeptoid Conformational Landscapes through Integrated Experiment and Simulation. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c00550] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sally Jiao
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, United States
| | - Audra DeStefano
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, United States
| | - Jacob I. Monroe
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, United States
| | - Mikayla Barry
- Department of Materials, University of California, Santa Barbara, California 93106, United States
| | - Nicholas Sherck
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, United States
| | - Thomas Casey
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Rachel A. Segalman
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, United States
- Department of Materials, University of California, Santa Barbara, California 93106, United States
| | - Songi Han
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, United States
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - M. Scott Shell
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, United States
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9
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Rinaldi J, Fernández I, Shin H, Sycz G, Gunawardana S, Kumarapperuma I, Paz JM, Otero LH, Cerutti ML, Zorreguieta Á, Ren Z, Klinke S, Yang X, Goldbaum FA. Dimer Asymmetry and Light Activation Mechanism in Brucella Blue-Light Sensor Histidine Kinase. mBio 2021; 12:e00264-21. [PMID: 33879593 DOI: 10.1128/mBio.00264-21] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Bacteria employ two-component systems (TCSs) to sense and respond to changes in their surroundings. At the core of the TCS signaling pathway is the multidomain sensor histidine kinase, where the enzymatic activity of its output domain is allosterically controlled by the input signal perceived by the sensor domain. The ability to sense and respond to environmental cues is essential for adaptation and survival in living organisms. In bacteria, this process is accomplished by multidomain sensor histidine kinases that undergo autophosphorylation in response to specific stimuli, thereby triggering downstream signaling cascades. However, the molecular mechanism of allosteric activation is not fully understood in these important sensor proteins. Here, we report the full-length crystal structure of a blue light photoreceptor LOV histidine kinase (LOV-HK) involved in light-dependent virulence modulation in the pathogenic bacterium Brucella abortus. Joint analyses of dark and light structures determined in different signaling states have shown that LOV-HK transitions from a symmetric dark structure to a highly asymmetric light state. The initial local and subtle structural signal originated in the chromophore-binding LOV domain alters the dimer asymmetry via a coiled-coil rotary switch and helical bending in the helical spine. These amplified structural changes result in enhanced conformational flexibility and large-scale rearrangements that facilitate the phosphoryl transfer reaction in the HK domain.
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10
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Hart JE, Gardner KH. Lighting the way: Recent insights into the structure and regulation of phototropin blue light receptors. J Biol Chem 2021; 296:100594. [PMID: 33781746 PMCID: PMC8086140 DOI: 10.1016/j.jbc.2021.100594] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 03/24/2021] [Accepted: 03/25/2021] [Indexed: 02/06/2023] Open
Abstract
The phototropins (phots) are light-activated kinases that are critical for plant physiology and the many diverse optogenetic tools that they have inspired. Phototropins combine two blue-light-sensing Light-Oxygen-Voltage (LOV) domains (LOV1 and LOV2) and a C-terminal serine/threonine kinase domain, using the LOV domains to control the catalytic activity of the kinase. While much is known about the structure and photochemistry of the light-perceiving LOV domains, particularly in how activation of the LOV2 domain triggers the unfolding of alpha helices that communicate the light signal to the kinase domain, many questions about phot structure and mechanism remain. Recent studies have made progress addressing these questions by utilizing small-angle X-ray scattering (SAXS) and other biophysical approaches to study multidomain phots from Chlamydomonas and Arabidopsis, leading to models where the domains have an extended linear arrangement, with the regulatory LOV2 domain contacting the kinase domain N-lobe. We discuss this and other advances that have improved structural and mechanistic understanding of phot regulation in this review, along with the challenges that will have to be overcome to obtain high-resolution structural information on these exciting photoreceptors. Such information will be essential to advancing fundamental understanding of plant physiology while enabling engineering efforts at both the whole plant and molecular levels.
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Affiliation(s)
- Jaynee E Hart
- Structural Biology Initiative, CUNY Advanced Science Research Center, New York, New York, USA
| | - Kevin H Gardner
- Structural Biology Initiative, CUNY Advanced Science Research Center, New York, New York, USA; Department of Chemistry and Biochemistry, City College of New York, New York, USA; PhD Programs in Biochemistry, Chemistry, and Biology, Graduate Center, City University of New York, New York, USA.
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11
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Bouillet S, Wu T, Chen S, Stock AM, Gao R. Structural asymmetry does not indicate hemiphosphorylation in the bacterial histidine kinase CpxA. J Biol Chem 2020; 295:8106-8117. [PMID: 32094228 DOI: 10.1074/jbc.ra120.012757] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 02/19/2020] [Indexed: 11/06/2022] Open
Abstract
Histidine protein kinases (HKs) are prevalent prokaryotic sensor kinases that are central to phosphotransfer in two-component signal transduction systems, regulating phosphorylation of response regulator proteins that determine the output responses. HKs typically exist as dimers and can potentially autophosphorylate at each conserved histidine residue in the individual protomers, leading to diphosphorylation. However, analyses of HK phosphorylation in biochemical assays in vitro suggest negative cooperativity, whereby phosphorylation in one protomer of the dimer inhibits phosphorylation in the second protomer, leading to ∼50% phosphorylation of the available sites in dimers. This negative cooperativity is often correlated with an asymmetric domain arrangement, a common structural characteristic of autophosphorylation states in many HK structures. In this study, we engineered covalent dimers of the cytoplasmic domains of Escherichia coli CpxA, enabling us to quantify individual species: unphosphorylated, monophosphorylated, and diphosphorylated dimers. Together with mathematical modeling, we unambiguously demonstrate no cooperativity in autophosphorylation of CpxA despite its asymmetric structures, indicating that these asymmetric domain arrangements are not linked to negative cooperativity and hemiphosphorylation. Furthermore, the modeling indicated that many parameters, most notably minor amounts of ADP generated during autophosphorylation reactions or present in ATP preparations, can produce ∼50% total phosphorylation that may be mistakenly attributed to negative cooperativity. This study also establishes that the engineered covalent heterodimer provides a robust experimental system for investigating cooperativity in HK autophosphorylation and offers a useful tool for testing how symmetric or asymmetric structural features influence HK functions.
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Affiliation(s)
- Sophie Bouillet
- Center for Advanced Biotechnology and Medicine, Department of Biochemistry and Molecular Biology, Rutgers University-Robert Wood Johnson Medical School, Piscataway, New Jersey 08854
| | - Ti Wu
- Center for Advanced Biotechnology and Medicine, Department of Biochemistry and Molecular Biology, Rutgers University-Robert Wood Johnson Medical School, Piscataway, New Jersey 08854
| | - Shaoxing Chen
- Center for Advanced Biotechnology and Medicine, Department of Biochemistry and Molecular Biology, Rutgers University-Robert Wood Johnson Medical School, Piscataway, New Jersey 08854
| | - Ann M Stock
- Center for Advanced Biotechnology and Medicine, Department of Biochemistry and Molecular Biology, Rutgers University-Robert Wood Johnson Medical School, Piscataway, New Jersey 08854
| | - Rong Gao
- Center for Advanced Biotechnology and Medicine, Department of Biochemistry and Molecular Biology, Rutgers University-Robert Wood Johnson Medical School, Piscataway, New Jersey 08854
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12
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Skalova T, Lengalova A, Dohnalek J, Harlos K, Mihalcin P, Kolenko P, Stranava M, Blaha J, Shimizu T, Martínková M. Disruption of the dimerization interface of the sensing domain in the dimeric heme-based oxygen sensor AfGcHK abolishes bacterial signal transduction. J Biol Chem 2020; 295:1587-1597. [PMID: 31914416 PMCID: PMC7008379 DOI: 10.1074/jbc.ra119.011574] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 12/30/2019] [Indexed: 12/17/2022] Open
Abstract
The heme-based oxygen sensor protein AfGcHK is a globin-coupled histidine kinase in the soil bacterium Anaeromyxobacter sp. Fw109-5. Its C-terminal functional domain exhibits autophosphorylation activity induced by oxygen binding to the heme-Fe(II) complex located in the oxygen-sensing N-terminal globin domain. A detailed understanding of the signal transduction mechanisms in heme-containing sensor proteins remains elusive. Here, we investigated the role of the globin domain's dimerization interface in signal transduction in AfGcHK. We present a crystal structure of a monomeric imidazole-bound AfGcHK globin domain at 1.8 Å resolution, revealing that the helices of the WT globin dimer are under tension and suggesting that Tyr-15 plays a role in both this tension and the globin domain's dimerization. Biophysical experiments revealed that whereas the isolated WT globin domain is dimeric in solution, the Y15A and Y15G variants in which Tyr-15 is replaced with Ala or Gly, respectively, are monomeric. Additionally, we found that although the dimerization of the full-length protein is preserved via the kinase domain dimerization interface in all variants, full-length AfGcHK variants bearing the Y15A or Y15G substitutions lack enzymatic activity. The combined structural and biophysical results presented here indicate that Tyr-15 plays a key role in the dimerization of the globin domain of AfGcHK and that globin domain dimerization is essential for internal signal transduction and autophosphorylation in this protein. These findings provide critical insights into the signal transduction mechanism of the histidine kinase AfGcHK from Anaeromyxobacter.
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Affiliation(s)
- Tereza Skalova
- Institute of Biotechnology of the Czech Academy of Sciences, v.v.i., Biocev, Vestec, 252 50 Czech Republic
| | - Alzbeta Lengalova
- Department of Biochemistry, Faculty of Science, Charles University, Prague 2, 128 43 Czech Republic
| | - Jan Dohnalek
- Institute of Biotechnology of the Czech Academy of Sciences, v.v.i., Biocev, Vestec, 252 50 Czech Republic
| | - Karl Harlos
- Division of Structural Biology, The Wellcome Trust Centre for Human Genetics, University of Oxford, OX3 7BN Oxford, United Kingdom
| | - Peter Mihalcin
- Department of Biochemistry, Faculty of Science, Charles University, Prague 2, 128 43 Czech Republic
| | - Petr Kolenko
- Institute of Biotechnology of the Czech Academy of Sciences, v.v.i., Biocev, Vestec, 252 50 Czech Republic; FNSPE, Czech Technical University in Prague, Brehova 7, Prague 1, 115 19 Czech Republic
| | - Martin Stranava
- Department of Biochemistry, Faculty of Science, Charles University, Prague 2, 128 43 Czech Republic
| | - Jan Blaha
- Department of Biochemistry, Faculty of Science, Charles University, Prague 2, 128 43 Czech Republic
| | - Toru Shimizu
- Department of Biochemistry, Faculty of Science, Charles University, Prague 2, 128 43 Czech Republic
| | - Markéta Martínková
- Department of Biochemistry, Faculty of Science, Charles University, Prague 2, 128 43 Czech Republic.
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Li X, Eyles SJ, Thompson LK. Hydrogen exchange of chemoreceptors in functional complexes suggests protein stabilization mediates long-range allosteric coupling. J Biol Chem 2019; 294:16062-16079. [PMID: 31506298 DOI: 10.1074/jbc.ra119.009865] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 09/08/2019] [Indexed: 11/06/2022] Open
Abstract
Bacterial chemotaxis receptors form extended hexagonal arrays that integrate and amplify signals to control swimming behavior. Transmembrane signaling begins with a 2-Å ligand-induced displacement of an α helix in the periplasmic and transmembrane domains, but it is unknown how the cytoplasmic domain propagates the signal an additional 200 Å to control the kinase CheA bound to the membrane-distal tip of the receptor. The receptor cytoplasmic domain has previously been shown to be highly dynamic as both a cytoplasmic fragment (CF) and within the intact chemoreceptor; modulation of its dynamics is thought to play a key role in signal propagation. This hydrogen deuterium exchange-MS (HDX-MS) study of functional complexes of CF, CheA, and CheW bound to vesicles in native-like arrays reveals that the CF is well-ordered only in its protein interaction region where it binds CheA and CheW. We observe rapid exchange throughout the rest of the CF, with both uncorrelated (EX2) and correlated (EX1) exchange patterns, suggesting the receptor cytoplasmic domain retains disorder even within functional complexes. HDX rates are increased by inputs that favor the kinase-off state. We propose that chemoreceptors achieve long-range allosteric control of the kinase through a coupled equilibrium: CheA binding in a kinase-on conformation stabilizes the cytoplasmic domain, and signaling inputs that destabilize this domain (ligand binding and demethylation) disfavor CheA binding such that it loses key contacts and reverts to a kinase-off state. This study reveals the mechanistic role of an intrinsically disordered region of a transmembrane receptor in long-range allostery.
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Affiliation(s)
- Xuni Li
- Department of Chemistry, University of Massachusetts Amherst, Amherst, Massachusetts 01003
| | - Stephen J Eyles
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, Massachusetts 01003
| | - Lynmarie K Thompson
- Department of Chemistry, University of Massachusetts Amherst, Amherst, Massachusetts 01003 .,Program in Molecular and Cellular Biology, University of Massachusetts Amherst, Amherst, Massachusetts 01003
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Fiebig A, Varesio LM, Alejandro Navarreto X, Crosson S. Regulation of the Erythrobacter litoralis DSM 8509 general stress response by visible light. Mol Microbiol 2019; 112:442-460. [PMID: 31125464 DOI: 10.1111/mmi.14310] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/20/2019] [Indexed: 01/23/2023]
Abstract
Extracytoplasmic function (ECF) sigma factors are environmentally responsive transcriptional regulators. In Alphaproteobacteria, σEcfG activates general stress response (GSR) transcription and protects cells from multiple stressors. A phosphorylation-dependent protein partner switching mechanism, involving HWE/HisKA_2-family histidine kinases, underlies σEcfG activation. The identity of these sensor kinases and the signals that regulate them remain largely uncharacterized. We have developed the aerobic anoxygenic photoheterotroph (AAP), Erythrobacter litoralis DSM 8509, as a comparative genetic model to investigate GSR. Using this system, we sought to define the role of visible light and a photosensory HWE kinase, LovK, in regulation of GSR transcription. We identified three HWE kinase genes that collectively control GSR: gsrK and lovK are activators, while gsrP is a repressor. In wild-type cells, GSR transcription is activated in the dark and nearly off in the light, and the opposing activities of gsrK and gsrP are sufficient to modulate GSR transcription in response to illumination. In the absence of gsrK and gsrP, lovK alone is sufficient to activate GSR transcription. lovK is a more robust activator in the dark, and light-dependent regulation by LovK requires that its N-terminal LOV domain be photochemically active. Our studies establish a role for visible light and an ensemble of HWE kinases in light-dependent regulation of GSR transcription in E. litoralis.
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Affiliation(s)
- Aretha Fiebig
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, 60637, USA
| | - Lydia M Varesio
- The Committee on Microbiology, The University of Chicago, Chicago, IL, 60637, USA
| | | | - Sean Crosson
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, 60637, USA.,The Committee on Microbiology, The University of Chicago, Chicago, IL, 60637, USA
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Dikiy I, Gardner KH. Shining light on the alphaproteobacterial general stress response: Comment on: Fiebig et al., Mol Microbiol, 2019. Mol Microbiol 2019; 112:438-441. [PMID: 31120626 DOI: 10.1111/mmi.14311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/20/2019] [Indexed: 11/26/2022]
Abstract
The general stress response (GSR) allows many bacterial species to react to myriad different stressors. In Alphaproteobacteria, this signaling pathway proceeds through the partner-switching PhyR-EcfG sigma-factor mechanism and is involved in multiple life processes, including virulence in Brucella abortus. To date, details of the alphaproteobacterial GSR signaling pathway have been determined using genetic and biochemical work on a diverse set of species distributed throughout the clade. Fiebig and co-workers establish Erythrobacter litoralis DSM 8509 as a genetically tractable lab strain and use it to both directly and indirectly delineate photoresponsive GSR pathways mediated by multiple HWE/HisKA_2 histidine kinases. The existence of a new phototrophic lab strain allows researchers to compare the GSR across different Alphaproteobacteria, as well as study the interplay between the GSR and phototrophy. Additionally, the discovery of new HWE/HisKA_2 kinases regulating the GSR poses new questions about how different stimuli feed into this widespread stress pathway.
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Affiliation(s)
- Igor Dikiy
- Structural Biology Initiative, CUNY Advanced Science Research Center, New York, NY, USA
| | - Kevin H Gardner
- Department of Chemistry and Biochemistry, City College of New York, New York, NY, USA.,Programs in Biochemistry, Biology and Chemistry, CUNY Graduate Center, New York, NY, USA
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