Discovery of a new light-driven Li+/Na+-pumping rhodopsin with DTG motif

Cho, Shin-Gyu; Shim, Jin-gon; Choun, Kimleng; Meas, Seanghun; Kang, Kun-Wook; Kim, Jihyun; Cho, Hyun-Suk; Jung, Kwang‐Hwan

doi:10.1016/j.jphotobiol.2021.112285

Cited by 5 publications

(14 citation statements)

References 54 publications

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“…Rhodopsin expression and purification procedures have been previously described [ 8 ]. The AbHeR WT, AbHeR mutants, and GR WT were expressed in E .…”

Section: Methodsmentioning

confidence: 99%

“…Previously reported methods for ITC analysis of microbial rhodopsin were followed with slight modifications [ 8 , 33 ]. Purified AbHeR WT, AbHeR mutants, and AbGS were completely exchanged with buffer SD using Amicon Ultra-4 10,000 MWCO centrifugal filter units and Amicon Ultra-4 30,000 MWCO centrifugal filter units, respectively.…”

Section: Methodsmentioning

confidence: 99%

“…The protocols for estimating p K a values of the counterion, preparation of RSO membrane vesicles, and the light-induced H + movement assay, have been described [ 8 ]. Absorption spectra of purified AbHeR were measured using a UV-VIS spectrophotometer (Shimadzu UV-2550, Japan).…”

Section: Methodsmentioning

confidence: 99%

“…Rhodopsin expression and purification procedures have been previously described [8]. The AbHeR WT, AbHeR mutants, and GR WT were expressed in E. coli C43 (DE3) cultured in LB medium containing 50 μg/mL ampicillin at 37˚C and 200 rpm.…”

Section: Protein Expression and Purificationmentioning

confidence: 99%

“…Light-driven type I rhodopsins have been described as H + , Cl -, and Na + pumps, light sensors, and channelrhodopsins. They typically contain conserved residues that are specific for the ion that they transport [6][7][8][9][10][11][12]. Microbial rhodopsins contain various critical residues, including those within the retinal-binding pocket, retinal covalent linkage, and counterions associated with retinal [13].…”

Section: Introductionmentioning

confidence: 99%

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Heliorhodopsin binds and regulates glutamine synthetase activity

et al. 2022

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Photoreceptors are light-sensitive proteins found in various organisms that respond to light and relay signals into the cells. Heliorhodopsin, a retinal-binding membrane protein, has been recently discovered, however its function remains unknown. Herein, we investigated the relationship between Actinobacteria bacterium IMCC26103 heliorhodopsin (AbHeR) and an adjacent glutamine synthetase (AbGS) in the same operon. We demonstrate that AbHeR binds to AbGS and regulates AbGS activity. More specifically, the dissociation constant (Kd) value of the binding between AbHeR and AbGS is 6.06 μM. Moreover, the absence of positively charged residues within the intracellular loop of AbHeR impacted Kd value as they serve as critical binding sites for AbGS. We also confirm that AbHeR up-regulates the biosynthetic enzyme activity of AbGS both in vitro and in vivo in the presence of light. GS is a key enzyme involved in nitrogen assimilation that catalyzes the conversion of glutamate and ammonia to glutamine. Hence, the interaction between AbHeR and AbGS may be critical for nitrogen assimilation in Actinobacteria bacterium IMCC26103 as it survives in low-nutrient environments. Overall, the findings of our study describe, for the first time, to the best of our knowledge, a novel function of heliorhodopsin as a regulatory rhodopsin with the capacity to bind and regulate enzyme activity required for nitrogen assimilation.

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“…Rhodopsin expression and purification procedures have been previously described [ 8 ]. The AbHeR WT, AbHeR mutants, and GR WT were expressed in E .…”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Protein Expression and Purificationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Heliorhodopsin binds and regulates glutamine synthetase activity

et al. 2022

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A subgroup of light-driven sodium pumps with an additional Schiff base counterion

Podoliak,

Lamm,

Marin

et al. 2024

Nat Commun

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Light-driven sodium pumps (NaRs) are unique ion-transporting microbial rhodopsins. The major group of NaRs is characterized by an NDQ motif and has two aspartic acid residues in the central region essential for sodium transport. Here we identify a subgroup of the NDQ rhodopsins bearing an additional glutamic acid residue in the close vicinity to the retinal Schiff base. We thoroughly characterize a member of this subgroup, namely the protein ErNaR from Erythrobacter sp. HL-111 and show that the additional glutamic acid results in almost complete loss of pH sensitivity for sodium-pumping activity, which is in contrast to previously studied NaRs. ErNaR is capable of transporting sodium efficiently even at acidic pH levels. X-ray crystallography and single particle cryo-electron microscopy reveal that the additional glutamic acid residue mediates the connection between the other two Schiff base counterions and strongly interacts with the aspartic acid of the characteristic NDQ motif. Hence, it reduces its pKa. Our findings shed light on a subgroup of NaRs and might serve as a basis for their rational optimization for optogenetics.

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Heliorhodopsin-mediated light-modulation of ABC transporter

Cho,

Kim,

Lee

et al. 2024

Nat Commun

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Heliorhodopsins (HeRs) have been hypothesized to have widespread functions. Recently, the functions for few HeRs have been revealed; however, the hypothetical functions remain largely unknown. Herein, we investigate light-modulation of heterodimeric multidrug resistance ATP-binding cassette transporters (OmrDE) mediated by Omithinimicrobium cerasi HeR. In this study, we classifiy genes flanking the HeR-encoding genes and identify highly conservative residues for protein–protein interactions. Our results reveal that the interaction between OcHeR and OmrDE shows positive cooperatively sequential binding through thermodynamic parameters. Moreover, light-induced OcHeR upregulates OmrDE drug transportation. Hence, the binding may be crucial to drug resistance in O. cerasi as it survives in a drug-containing habitat. Overall, we unveil a function of HeR as regulatory rhodopsin for multidrug resistance. Our findings suggest potential applications in optogenetic technology.

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Discovery of a new light-driven Li+/Na+-pumping rhodopsin with DTG motif

Cited by 5 publications

References 54 publications

Heliorhodopsin binds and regulates glutamine synthetase activity

Heliorhodopsin binds and regulates glutamine synthetase activity

A subgroup of light-driven sodium pumps with an additional Schiff base counterion

Heliorhodopsin-mediated light-modulation of ABC transporter

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