scholarly journals Plant High-Affinity Potassium (HKT) Transporters Involved in Salinity Tolerance: Structural Insights to Probe Differences in Ion Selectivity

2013 ◽  
Vol 14 (4) ◽  
pp. 7660-7680 ◽  
Author(s):  
Shane Waters ◽  
Matthew Gilliham ◽  
Maria Hrmova
Keyword(s):  
Salinity Tolerance ◽  
Ion Selectivity ◽  
High Affinity ◽  
Structural Insights ◽  
Hkt Transporters

Nomenclature for HKT transporters, key determinants of plant salinity tolerance

2006 ◽  
Vol 11 (8) ◽  
pp. 372-374 ◽  
Author(s):  
J. Damien Platten ◽  
Olivier Cotsaftis ◽  
Pierre Berthomieu ◽  
Hans Bohnert ◽  
Romola J. Davenport ◽  
...  
Keyword(s):  
Salinity Tolerance ◽  
Hkt Transporters

Nanomolar Levels of Dimethylsulfoniopropionate, Dimethylsulfonioacetate, and Glycine Betaine Are Sufficient To Confer Osmoprotection to Escherichia coli

1999 ◽  
Vol 65 (8) ◽  
pp. 3304-3311 ◽  
Author(s):  
Anne Cosquer ◽  
Vianney Pichereau ◽  
Jean-Alain Pocard ◽  
Jacques Minet ◽  
Michel Cormier ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Salinity Tolerance ◽  
Glycine Betaine ◽  
Standard Laboratory ◽  
E Coli ◽  
High Affinity ◽  
Bacterial Cultures ◽  
Transport Studies ◽  
Ecological Implications ◽  
Substrate Concentrations

ABSTRACT We combined the use of low inoculation titers (300 ± 100 CFU/ml) and enumeration of culturable cells to measure the osmoprotective potentialities of dimethylsulfoniopropionate (DMSP), dimethylsulfonioacetate (DMSA), and glycine betaine (GB) for salt-stressed cultures of Escherichia coli. Dilute bacterial cultures were grown with osmoprotectant concentrations that encompassed the nanomolar levels of GB and DMSP found in nature and the millimolar levels of osmoprotectants used in standard laboratory osmoprotection bioassays. Nanomolar concentrations of DMSA, DMSP, and GB were sufficient to enhance the salinity tolerance of E. coli cells expressing only the ProU high-affinity general osmoporter. In contrast, nanomolar levels of osmoprotectants were ineffective with a mutant strain (GM50) that expressed only the low-affinity ProP osmoporter. Transport studies showed that DMSA and DMSP, like GB, were taken up via both ProU and ProP. Moreover, ProU displayed higher affinities for the three osmoprotectants than ProP displayed, and ProP, like ProU, displayed much higher affinities for GB and DMSA than for DMSP. Interestingly, ProP did not operate at substrate concentrations of 200 nM or less, whereas ProU operated at concentrations ranging from 1 nM to millimolar levels. Consequently,proU + strains of E. coli, but not the proP + strain GM50, could also scavenge nanomolar levels of GB, DMSA, and DMSP from oligotrophic seawater. The physiological and ecological implications of these observations are discussed.

scholarly journals Structural insights into the mechanisms of CNBD channel function

2017 ◽  
Vol 150 (2) ◽  
pp. 225-244 ◽  
Author(s):  
Zachary M. James ◽  
William N. Zagotta
Keyword(s):  
Cyclic Nucleotide ◽  
Ion Selectivity ◽  
K Channel ◽  
Hcn Channels ◽  
Nucleotide Binding Domain ◽  
Physiological Processes ◽  
Structural Framework ◽  
Voltage Dependent ◽  
Compare And Contrast ◽  
Structural Insights

Cyclic nucleotide-binding domain (CNBD) channels are a family of ion channels in the voltage-gated K+ channel superfamily that play crucial roles in many physiological processes. CNBD channels are structurally similar but functionally very diverse. This family includes three subfamilies: (1) the cyclic nucleotide-gated (CNG) channels, which are cation-nonselective, voltage-independent, and cyclic nucleotide-gated; (2) the hyperpolarization-activated cyclic nucleotide-gated (HCN) channels, which are weakly K+ selective, hyperpolarization-activated, and cyclic nucleotide-gated; and (3) the ether-à-go-go-type (KCNH) channels, which are strongly K+ selective, depolarization-activated, and cyclic nucleotide-independent. Recently, several high-resolution structures have been reported for intact CNBD channels, providing a structural framework to better understand their diverse function. In this review, we compare and contrast the recent structures and discuss how they inform our understanding of ion selectivity, voltage-dependent gating, and cyclic nucleotide–dependent gating within this channel family.

scholarly journals The Bionic Water Channel of Ultra-Short, High Affinity Carbon Nanotubes with High Water Permeability and Proton Selectivity

2020 ◽  
Vol 13 (1) ◽  
pp. 102
Author(s):  
Guangli Liu ◽  
Bin Zhou ◽  
Jinwei Liu ◽  
Huazhang Zhao
Keyword(s):  
Carbon Nanotubes ◽  
Water Permeability ◽  
Lipid Membrane ◽  
Ion Selectivity ◽  
Biological Membrane ◽  
Water Channel ◽  
High Water ◽  
Structural Features ◽  
High Affinity ◽  
Salt Ions

The development of the bionic water channel aims to replace the possible use of natural aquaporins (AQPs) for water purification, while retaining the ability of natural AQPs to carry out ultra-fast water transport and repel ions. Carbon nanotube channels (CNTCs) are a convenient membrane-based model system for studying nano-fluidic transport that replicates a number of key structural features of biological membrane channels. In this report, we describe protocols for CNTCs synthesis by ultrasound-assisted cutting of long CNTs in the presence of lipid amphiphiles. CNTCs have a similar thickness to the lipid membrane and high affinity for it. The ultra-short high-affinity CNTCs have high permeability and ion selectivity. The water permeability of the CNTCs is 1936 ± 123 μm/s, which is 2.3 times that of natural AQPs, and completely rejects salt ions. In general, carbon nanotubes represent a multifunctional nanopore building module for creating high-ranking functional bionic materials. This study has reference significance for the design of new bionic water channel and the actual development of bionic membrane based on CNTs.

Structural insights intoAspergillus fumigatuslectin specificity: AFL binding sites are functionally non-equivalent

2015 ◽  
Vol 71 (3) ◽  
pp. 442-453 ◽  
Author(s):  
Josef Houser ◽  
Jan Komarek ◽  
Gianluca Cioci ◽  
Annabelle Varrot ◽  
Anne Imberty ◽  
...  
Keyword(s):  
Amino Acid ◽  
Binding Sites ◽  
Opportunistic Pathogen ◽  
Biotechnological Applications ◽  
Binding Properties ◽  
High Affinity ◽  
Lectin Family ◽  
Structural Insights ◽  
Specific Ligand ◽  
Micromolar Range

TheAspergillus fumigatuslectin AFL was recently described as a new member of the AAL lectin family. As a lectin from an opportunistic pathogen, it might play an important role in the interaction of the pathogen with the human host. A detailed study of structures of AFL complexed with several monosaccharides and oligosaccharides, including blood-group epitopes, was combined with affinity data from SPR and discussed in the context of previous findings. Its six binding sites are non-equivalent, and owing to minor differences in amino-acid composition they exhibit a marked difference in specific ligand recognition. AFL displays a high affinity in the micromolar range towards oligosaccharides which were detected in plants and also those bound on the human epithelia. All of these results indicate AFL to be a complex member of the lectin family and a challenging target for future medical research and, owing to its binding properties, a potentially useful tool in specific biotechnological applications.

Structural insights into the high affinity binding of cardiotonic steroids to the Na+,K+-ATPase

2011 ◽  
Vol 174 (2) ◽  
pp. 296-306 ◽  
Author(s):  
Laure Yatime ◽  
Mette Laursen ◽  
J. Preben Morth ◽  
Mikael Esmann ◽  
Poul Nissen ◽  
...  
Keyword(s):  
Affinity Binding ◽  
High Affinity Binding ◽  
High Affinity ◽  
Structural Insights
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