scholarly journals Preference of Proteomonas sulcata anion channelrhodopsin for NO3− revealed using a pH electrode method

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Chihiro Kikuchi ◽  
Hina Kurane ◽  
Takuma Watanabe ◽  
Makoto Demura ◽  
Takashi Kikukawa ◽  
...  
Keyword(s):  
Transmembrane Helix ◽  
Anion Transport ◽  
Yeast Cells ◽  
Ion Pump ◽  
Transport Activity ◽  
Electrode Method ◽  
Anion Transport Activity ◽  
Living Organisms ◽  
Stable Forms ◽  
Ph Electrode

AbstractIon channel proteins are physiologically important molecules in living organisms. Their molecular functions have been investigated using electrophysiological methods, which enable quantitative, precise and advanced measurements and thus require complex instruments and experienced operators. For simpler and easier measurements, we measured the anion transport activity of light-gated anion channelrhodopsins (ACRs) using a pH electrode method, which has already been established for ion pump rhodopsins. Using that method, we successfully measured the anion transport activity and its dependence on the wavelength of light, i.e. its action spectra, and on the anion species, i.e. its selectivity or preference, of several ACRs expressed in yeast cells. In addition, we identified the strong anion transport activity and the preference for NO3− of an ACR from a marine cryptophyte algae Proteomonas sulcata, named PsuACR_353. Such a preference was discovered for the first time in microbial pump- or channel-type rhodopsins. Nitrate is one of the most stable forms of nitrogen and is used as a nitrogen source by most organisms including plants. Therefore, PsuACR_353 may play a role in NO3− transport and might take part in NO3−-related cellular functions in nature. Measurements of a mutant protein revealed that a Thr residue in the 3rd transmembrane helix, which corresponds to Cys102 in GtACR1, contributed to the preference for NO3−. These findings will be helpful to understand the mechanisms of anion transport, selectivity and preference of PsuACR_353.

scholarly journals Preference of Proteomonas Sulcata Anion Channelrhodopsin for Nitrate Revealed Using a pH Electrode Method

2021 ◽  
Author(s):  
Chihiro Kikuchi ◽  
Hina Kurane ◽  
Takuma Watanabe ◽  
Makoto Demura ◽  
Takashi Kikukawa ◽  
...  
Keyword(s):  
Transmembrane Helix ◽  
Anion Transport ◽  
Yeast Cells ◽  
Ion Pump ◽  
Transport Activity ◽  
Electrode Method ◽  
Anion Transport Activity ◽  
Living Organisms ◽  
Stable Forms ◽  
Ph Electrode

Abstract Ion channel proteins are physiologically important molecules in living organisms. Their molecular functions have been investigated using electrophysiological methods, which enable quantitative, precise and advanced measurements and thus require complex instruments and experienced operators. For simpler and easier measurements, we measured the anion transport activity of light-gated anion channelrhodopsins (ACRs) using a pH electrode method, which has already been established for ion pump rhodopsins. Using that method, we successfully measured the anion transport activity and its dependence on the wavelength of light, i.e. its action spectra, and on the anion species, i.e. its selectivity or preference, of several ACRs expressed in yeast cells. In addition, we identified the strong anion transport activity and the preference for NO3- of an ACR from a marine cryptophyte algae Proteomonas sulcata, named PsuACR_353. Such a preference was discovered for the first time in microbial pump- or channel-type rhodopsins. Nitrate is one of the most stable forms of nitrogen and is used as a nitrogen source by most organisms including plants. Therefore, PsuACR_353 may play a role in NO3- transport and might take part in NO3--related cellular functions in nature. Measurements of a mutant protein revealed that a Thr residue in the 3rd transmembrane helix, which corresponds to Cys102 in GtACR1, contributed to the preference for NO3-. These findings will be helpful to understand the mechanisms of anion transport, selectivity and preference of PsuACR_353.

scholarly journals Band 3 HT, a human red-cell variant associated with acanthocytosis and increased anion transport, carries the mutation Pro-868→Leu in the membrane domain of band 3

1993 ◽  
Vol 293 (2) ◽  
pp. 317-320 ◽  
Author(s):  
L J Bruce ◽  
M M Kay ◽  
C Lawrence ◽  
M J Tanner
Keyword(s):  
Cell Shape ◽  
Band 3 ◽  
Anion Transport ◽  
Red Cell ◽  
Transport Activity ◽  
Binding Properties ◽  
Red Cell Shape ◽  
Disulphonic Acid ◽  
Anion Transport Activity ◽  
Cell Variant

1. We have studied band 3 HT, a human red-cell band 3 variant with increased M(r), which is associated with abnormal red-cell shape (acanthocytosis) and increased anion-transport activity. 2. We have shown that the increased M(r) does not result from the presence of the band 3 Memphis mutation, and that the variant band 3 is covalently labelled by 4,4′-di-isothiocyanato-1,2-diphenylethane-2,2′-disulphonic acid (H2DIDS) less readily than normal. 3. cDNA cloning studies show that band 3 HT results from the mutation Pro-868-->Leu, and the possible significance of the mutation in the altered anion-transport activity and cytoskeleton binding properties of band 3 HT is discussed.

Further Studies on Zn2+-Mediated Domain–Domain Communication in Human Erythrocyte Band 3

1998 ◽  
Vol 18 (5) ◽  
pp. 265-277
Author(s):  
Hong Xu ◽  
Xujia Zhang ◽  
Fu Yu Yang
Keyword(s):  
Conformational Change ◽  
Human Erythrocyte ◽  
Cytoplasmic Domain ◽  
Band 3 ◽  
Anion Transport ◽  
Intrinsic Fluorescence ◽  
Transport Activity ◽  
Membrane Domain ◽  
Nmr Study ◽  
Anion Transport Activity

Human erythrocyte band 3 is purified and reconstituted into vesicles, forming right-side-out proteoliposomes. Zn2+ entrapped inside the proteoliposomes inhibits the anion transport activity of band 3, and removal of the cytoplasmic domain of band 3 is able to diminish Zn2+ inhibition. Thus, the inhibition of activity of band 3 results from the Zn2+ induced conformational change of the cytoplasmic domain, which in turn is transmitted to the membrane domain. The results of intrinsic fluorescence and its quenching by HB and the 35Cl NMR study indicate that the cytoplasmic domain is essential for the conformational change induced by Zn2+.SH-blocking reagents, CH3I and GSSG, are used to modify the cytoplasmic domain, where they specifically bind to Cys201 and Cys317. It is observed that the Zn2+ induced inhibition of anion transport activity is blocked. This demonstrates that Cys201 and Cys317 are required in Zn2+-mediated domain–domain communication.

scholarly journals Transmembrane Fluoride Transport by a Cyclic Azapeptide With Two β-Turns

2021 ◽  
Vol 8 ◽  
Author(s):  
Zhixing Zhao ◽  
Miaomiao Zhang ◽  
Bailing Tang ◽  
Peimin Weng ◽  
Yueyang Zhang ◽  
...  
Keyword(s):  
Chloride Transport ◽  
Anion Transport ◽  
Bacterial Survival ◽  
Transport Activity ◽  
Selective Electrode ◽  
Design And Synthesis ◽  
Anion Transporters ◽  
Host Compound ◽  
Anion Transport Activity ◽  
Fluoride Ion Selective Electrode

Diverse classes of anion transporters have been developed, most of which focus on the transmembrane chloride transport due to its significance in living systems. Fluoride transport has, to some extent, been overlooked despite the importance of fluoride channels in bacterial survival. Here, we report the design and synthesis of a cyclic azapeptide (a peptide-based N-amidothiourea, 1), as a transporter for fluoride transportation through a confined cavity that encapsulates fluoride, together with acyclic control compounds, the analogs 2 and 3. Cyclic receptor 1 exhibits more stable β-turn structures than the control compounds 2 and 3 and affords a confined cavity containing multiple inner –NH protons that serve as hydrogen bond donors to bind anions. It is noteworthy that the cyclic receptor 1 shows the capacity to selectively transport fluoride across a lipid bilayer on the basis of the osmotic and fluoride ion-selective electrode (ISE) assays, during which an electrogenic anion transport mechanism is found operative, whereas no transmembrane transport activity was found with 2 and 3, despite the fact that 2 and 3 are also able to bind fluoride via the thiourea moieties. These results demonstrate that the encapsulation of an anionic guest within a cyclic host compound is key to enhancing the anion transport activity and selectivity.

Hydrazones in anion transporters: the detrimental effect of a second binding site

2021 ◽  
Vol 19 (38) ◽  
pp. 8324-8337
Author(s):  
Luis Martínez-Crespo ◽  
Lau Halgreen ◽  
Márcio Soares ◽  
Igor Marques ◽  
Vítor Félix ◽  
...  
Keyword(s):  
Binding Site ◽  
Functional Groups ◽  
Detrimental Effect ◽  
Anion Transport ◽  
Transport Activity ◽  
Anion Transporters ◽  
Anion Transport Activity

The effect of hydrazones and related functional groups on the anion transport activity of thioureas is presented.

scholarly journals QSAR analysis of substituent effects on tambjamine anion transporters

2016 ◽  
Vol 7 (2) ◽  
pp. 1600-1608 ◽  
Author(s):  
Nicola J. Knight ◽  
Elsa Hernando ◽  
Cally J. E. Haynes ◽  
Nathalie Busschaert ◽  
Harriet J. Clarke ◽  
...  
Keyword(s):  
Structural Parameters ◽  
Substituent Effects ◽  
Anion Transport ◽  
Transport Activity ◽  
Qsar Analysis ◽  
Anion Transporters ◽  
Anion Transport Activity

A QSAR analysis of the transmembrane anion transport activity of 43 synthetic tambjamine analogs allowed rationalization of this activity according to their lipophilicity and structural parameters.

scholarly journals A recurrent ABCC2 p.G693R mutation resulting in loss of function of MRP2 and hyperbilirubinemia in Dubin-Johnson syndrome in China

2020 ◽  
Author(s):  
Lina Wu ◽  
Yanmeng Li ◽  
Yi Song ◽  
Donghu Zhou ◽  
Siyu Jia ◽  
...  
Keyword(s):  
Cellular Localization ◽  
Organic Anion ◽  
Autosomal Recessive Disorder ◽  
Anion Transport ◽  
Causative Mutation ◽  
Loss Of Function ◽  
Organic Anion Transport ◽  
Transport Activity ◽  
Johnson Syndrome ◽  
Anion Transport Activity

Abstract Background: Dubin-Johnson syndrome (DJS) is a rare autosomal recessive disorder characterized by predominantly conjugated hyperbilirubinemia that is caused by pathogenic mutations in the adenosine triphosphate-binding cassette subfamily C member 2 ( ABCC2 ) gene, which encodes multidrug resistance-associated protein 2 (MRP2). However, little is known about the causative mutation of DJS in China. Recently, we have reported ABCC2 p.G693R mutation in two unrelated cases. In the present study, we investigated the pathogenicity of the ABCC2 p.G693R mutation in DJS in China. Methods: Clinical and genetic analysis was conducted for the two patients with the ABCC2 p.G693R mutation. Whole exome sequencing for mutations in other known hyperbilirubinemia-related genes was conducted for the cases with ABCC2 p.G693R. Expression and cellular localization of the mutant MRP2 p.G693R were analyzed by Western blotting and immunofluorescence assay, respectively. Organic anion transport activity was evaluated by the analysis of glutathione-conjugated-monochlorobimane. Results: The two DJS patients with ABCC2 p.G693R mutation, which was conserved among different species, showed typical hyperbilirubinemia phenotype. No pathogenic mutation was identified in the other known hyperbilirubinemia related genes. Functional studies in three cell lines showed that the expression, localization and the organic anion transport activity were significantly compromised by MRP2 p.G693R mutation compared with wild-type MRP2. Conclusions: The recurrent ABCC2 p.G693R mutation is associated with loss of function of the MRP2 protein and may result in hyperbilirubinemia in DJS in China.

Exhaustive-exercise-induced oxidative stress alteration of erythrocyte oxygen release capacity

2018 ◽  
Vol 96 (9) ◽  
pp. 953-962 ◽  
Author(s):  
Yanlian Xiong ◽  
Yanlei Xiong ◽  
Yueming Wang ◽  
Yajin Zhao ◽  
Yaojin Li ◽  
...  
Keyword(s):  
Carbonic Anhydrase ◽  
Band 3 ◽  
Anion Transport ◽  
Kinetic Properties ◽  
Oxygen Release ◽  
Transport Activity ◽  
Running Exercise ◽  
Release Capacity ◽  
Anion Transport Activity ◽  
2,3 Dpg

The aim of the present study was to explore the effect of exhaustive running exercise in the oxygen release capacity of rat erythrocytes. Rats were divided into sedentary control, moderate running exercise, and exhaustive running exercise groups. The thermodynamic and kinetic properties of the erythrocyte oxygen release process of the different groups were tested. We also determined the degree of band-3 oxidation and phosphorylation, anion transport activity, and carbonic anhydrase isoform II activity. Biochemical studies suggested that exhaustive running significantly increased oxidative injury parameters in thiobarbituric acid reactive substances and methaemoglobin levels. Furthermore, exhaustive running significantly decreased anion transport activity and carbonic anhydrase isoform II activity. Thermodynamic analysis indicated that erythrocytes oxygen release ability also significantly increased due to elevated 2,3-DPG level after exhaustive running. Kinetic analysis indicated that exhaustive running resulted in significantly decreased T50 value. We presented evidence that exhaustive running remarkably impacted thermodynamic and kinetic properties of RBC oxygen release. In addition, changes in 2,3-DPG levels and band-3 oxidation and phosphorylation could be the driving force for exhaustive-running-induced alterations in erythrocyte oxygen release thermodynamic and kinetic properties.

scholarly journals Transport activity of chimaeric AE2-AE3 chloride/bicarbonate anion exchange proteins

2003 ◽  
Vol 371 (3) ◽  
pp. 687-696 ◽  
Author(s):  
Jocelyne FUJINAGA ◽  
Frederick B. LOISELLE ◽  
Joseph R. CASEY
Keyword(s):  
Plasma Membrane ◽  
Cell Surface ◽  
Cytoplasmic Domain ◽  
Anion Transport ◽  
Transport Activity ◽  
Surface Processing ◽  
Hek 293 ◽  
Hek 293 Cells ◽  
293 Cells ◽  
Anion Transport Activity

Chloride/bicarbonate anion exchangers (AEs), found in the plasma membrane of most mammalian cells, are involved in pH regulation and bicarbonate metabolism. Although AE2 and AE3 are highly similar in sequence, AE2-transport activity was 10-fold higher than AE3 (41 versus 4 mM · min−1 respectively), when expressed by transient transfection of HEK-293 cells. AE2–AE3 chimaeras were constructed to define the region responsible for differences in transport activity. The level of AE2 expression was approx. 30% higher than that of AE3. Processing to the cell surface, studied by chemical labelling and confocal microscopy, showed that AE2 is processed to the cell surface approx. 8-fold more efficiently than AE3. The efficiency of cell-surface processing was dependent on the cytoplasmic domain, since the AE2 domain conferred efficient processing upon the AE3 membrane domain, with a predominant role for amino acids 322–677 of AE2. AE2 that was expressed in HEK-293 cells was glycosylated, but little of AE3 was. However, AE2 expressed in the presence of the glycosylation inhibitor, tunicamycin, was not glycosylated, yet retained 85 ± 8% of anion-transport activity. Therefore glycosylation has little, if any, role in the cell-surface processing or activity of AE2 or AE3. We conclude that the low anion-transport activity of AE3 in HEK-293 cells is due to low level processing to the plasma membrane, possibly owing to protein interactions with the AE3 cytoplasmic domain.

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