Summary Only graminaceous monocots possess the Strategy II iron (Fe)‐uptake system in which Fe is absorbed by roots as an 3+ ‐phytosiderophore. In spite of being a plant, however, rice ( Oryza sativa ) contains previously identified 2+ transporter OsIRT1. this study, we isolated OsIRT2 gene from rice, highly homologous to OsIRT1 . Real‐time PCR analysis revealed that and are expressed predominantly roots, these transporters induced low‐Fe conditions. When yeast Saccharomyces cerevisiae...

Rice (Oryza sativa) is indispensable in the diet of most world's population. Thus, it an important target which to alter iron (Fe) uptake and homeostasis, so as increase Fe accumulation grain. We previously isolated OsYSL2, a functional [Fe(II)]- manganese [Mn(II)]-nicotianamine complex transporter that expressed phloem cells developing seeds. produced RNAi (OsYSL2i) overexpression lines (OXOsYSL2) OsYSL2. At vegetative stage OsYSL2i line, Mn concentrations were decreased shoots,...

Mugineic acid family phytosiderophores (MAs) are metal chelators that produced in graminaceous plants response to iron (Fe) deficiency, but current evidence regarding secretion of MAs during zinc (Zn) deficiency is contradictory. Our studies using HPLC analysis showed Zn induces the synthesis and barley plants. The levels HvNAS1, HvNAAT-A, HvNAAT-B, HvIDS2 HvIDS3 transcripts, which encode enzymes involved MAs, were increased Zn-deficient roots. Studies genes methionine cycle microarray...

Deoxymugineic acid (DMA) is a member of the mugineic family phytosiderophores (MAs), which are natural metal chelators produced by graminaceous plants. Rice secretes DMA in response to Fe deficiency take up form Fe(III)-MAs complex. In contrast with barley, roots secrete MAs Zn deficiency, amount secreted rice was slightly decreased under conditions low supply. There concomitant increase endogenous shoots, suggesting that plays role translocation within Zn-deficient The expression OsNAS1 and...

Iron (Fe) deficiency is a worldwide agricultural problem on calcareous soils with low-Fe availability due to high soil pH. Rice plants use well documented phytosiderophore-based system (Strategy II) take up Fe from the and also possess direct Fe2+ transport system. are extremely susceptible supply, however, because of low phytosiderophore secretion Fe3+ reduction activity. A yeast chelate-reductase gene refre1/372, selected for better performance at pH, was fused promoter Fe-regulated...

The real-time translocation of iron (Fe) in barley (Hordeum vulgare L. cv. Ehimehadaka no. 1) was visualized using the positron-emitting tracer 52Fe and a imaging system (PETIS). PETIS allowed us to monitor Fe non-destructively under various conditions. In all cases, first accumulated at basal part shoot, suggesting that this region may play an important role distribution graminaceous plants. Fe-deficient showed greater from roots shoots than did Fe-sufficient barley, demonstrating...

In organisms, ion transporters play essential roles in the generation and dissipation of gradients across cell membranes. Microbial rhodopsins selectively transport cognate ions using solar energy, which substrate identified to date have been confined monovalent such as H+, Na+, Cl–. Here we report a novel rhodopsin from cyanobacterium Synechocystis sp. PCC 7509, inwardly transports polyatomic divalent sulfate ion, SO42–, with changes its spectroscopic properties both unphotolyzed photolyzed...

There are two types of membrane-embedded ion transport machineries in nature. The pumps generate electrochemical potential by energy-coupled active transportation, while the channels produce action stimulus-dependent passive transportation. About 80% amino acid residues light-driven proton pump archaerhodopsin-3 (AR3) and light-gated cation channel channelrhodopsin (ChR) differ although they share close similarity architecture. Therefore, question arises: How can these proteins function...

Gloeobacter rhodopsin (GR) is a eubacterial proton pump having highly conserved histidine near the retinal Schiff base counter-ion, aspartate. Various interactions between His and Asp of have been reported. Here, we showed pH-dependent trimer/monomer transition GR in presence dodecyl-β-D-maltoside by size-exclusion chromatography. The pH dependence was closely related to protonation state Asp121. For H87M mutant, disappeared monomer became dominant. We concluded that formation or breaking...

A new group of microbial rhodopsins named xenorhodopsins (XeR), which are closely related to the cyanobacterial Anabaena sensory rhodopsin, show a light-driven "inward" proton transport activity, as reported for one representative this from Parvularcula oceani (PoXeR). In study, we functionally and spectroscopically characterized member XeR clade marine bacterium Rubricoccus marinus SG-29T (RmXeR). Escherichia coli cells expressing recombinant RmXeR showed light-induced alkalization cell...

Recently, one of the interferon-induced transmembrane (IFITM) family proteins, IFITM3, has become an important target for activity against influenza A (H1N1) virus infection. In this protein, a post-translational modification by fatty acids covalently attached to cysteine, termed S-palmitoylation, plays crucial role antiviral activity. IFITM3 possesses three cysteine residues S-palmitoylation in first (TM1) domain and cytoplasmic (CP) loop. Because these cysteines are well conserved...

Chloride transport by microbial rhodopsins is actively being researched to understand how light energy converted drive ion pumping across cell membranes. pumps have been identified in archaea and eubacteria, there are similarities differences the active site structures between these groups. Thus, it has not clarified whether a common mechanism underlies pump processes for all chloride-pumping rhodopsins. Here, we applied Raman optical activity (ROA) spectroscopy two chloride pumps, Nonlabens...

Abstract Until now, the real-time uptake and movement of manganese (Mn), an essential plant nutrient, has not been documented in plants. In this study, translocation Mn barley (Hordeum vulgare L. cv. Ehimehadaka no. 1) was visualized using positron-emitting tracer 52Mn a imaging system (PETIS). PETIS allowed non-destructive monitoring under various conditions. all cases, first accumulated discrimination center (DC) at basal portion shoot, suggesting that region may play important role...

Several new retinal-based photoreceptor proteins that act as light-driven electrogenic halide ion pumps have recently been discovered. Some of them, called "NTQ" rhodopsins, contain a conserved Asn–Thr–Gln motif in the third or C-helix. In this study, we investigated photochemical characteristics an NTQ rhodopsin, Nonlabens marinus rhodopsin 3 (NM-R3), which was discovered N. S1-08T strain, using static and time-resolved spectroscopic techniques. We demonstrate NM-R3 binds Cl– vicinity...

Abstract Rhodopsins are proteins that contain seven transmembrane domains with a chromophore retinal and function as photoreceptors for light-energy conversion light-signal transduction in wide variety of organisms. Here we characterized phylogenetically distinctive new rhodopsin from the thermophilic eubacterium Rubrobacter xylanophilus DSM 9941 T was isolated thermally polluted water. Although R. (RxR) is Actinobacteria, it located between eukaryotic archaeal rhodopsins phylogenetic tree....

Assembly is one of the keys to understand biological molecules, and it takes place in spatial temporal domains upon stimulation. Microbial rhodopsin (also called retinal protein) a membrane-embedded protein that has chromophore within seven-transmembrane α-helices shows homo-, di-, tri-, penta-, hexameric assemblies. Those assemblies are closely related critical physiological properties such as stabilizing structure regulating their photoreaction dynamics. Here we investigated assembly...

Thermophilic rhodopsin (TR) is a light-driven proton pump from the extreme thermophile Thermus thermophilus JL-18. Previous studies on TR solubilized with detergent showed that protein exhibits high thermal stability and forms trimer at room temperature but irreversibly dissociates into monomers when incubated physiological (75 °C). In present study, we used resonance Raman (RR) spectroscopy, solid-state NMR high-speed atomic force microscopy to analyze oligomeric structure of in lipid...

Abstract Many microbial rhodopsins self-oligomerize, but the functional consequences of oligomerization have not been well clarified. We examined effects a H + pump, Gloeobacter rhodopsin (GR), by using nanodisc containing trimeric and monomeric GR. The monomerization did appear to affect unphotolyzed However, we found significant impact on photoreaction: GR showed faint M intermediate formation negligible transfer reactions. These changes reflected elevated pKa Asp121 residue, whose...

For membrane transporters, substrate uptake and release reactions are major events during their transport cycles. Despite the functional importance of these events, it is difficult to identify relevant structural intermediates because requirements experimental methods, which detect timing formation decay release. We report successfully achieving this for light-driven Na+ pump rhodopsin (NaR). Here, a Na+-selective membrane, consists polyvinyl chloride ionophore, was employed When one side...

Light-driven ion-pumping rhodopsins are widely distributed among bacteria, archaea, and eukaryotes in the euphotic zone of aquatic environment. H+-pumping rhodopsin (proteorhodopsin: PR), Na+-pumping (NaR), Cl--pumping (ClR) have been found marine which suggests that these genes evolved independently ocean. Putative microbial were identified genome sequences Cytophagia. In present study, one was heterologously expressed Escherichia coli cells protein named Rubricoccus marinus halorhodopsin...