Insights in KIR2.1 channel structure and function by an evolutionary approach; cloning and functional characterization of the first reptilian inward rectifier channel KIR2.1, derived from the California kingsnake (Lampropeltis getula californiae)

2014 ◽  
Vol 452 (4) ◽  
pp. 992-997 ◽  
Author(s):  
Marien J.C. Houtman ◽  
Sanne M. Korte ◽  
Yuan Ji ◽  
Bart Kok ◽  
Marc A. Vos ◽  
...  
Keyword(s):  
Functional Characterization ◽  
Structure And Function ◽  
Inward Rectifier ◽  
Channel Structure ◽  
Evolutionary Approach ◽  
And Function ◽  
Kir2.1 Channel ◽  
Lampropeltis Getula

Genomic analysis of nucleoside transporters in Diptera and functional characterization of DmENT2, a Drosophila equilibrative nucleoside transporter

2007 ◽  
Vol 28 (3) ◽  
pp. 337-347 ◽  
Author(s):  
Jerry Machado ◽  
Parween Abdulla ◽  
W. J. Brad Hanna ◽  
Arthur J. Hilliker ◽  
Imogen R. Coe
Keyword(s):  
Sequence Similarity ◽  
Functional Characterization ◽  
Genomic Analysis ◽  
Structure And Function ◽  
Nucleoside Transporters ◽  
Nucleoside Transport ◽  
Nucleoside Transporter ◽  
Nucleoside Transport Inhibitors ◽  
And Function

The recent completion of genome sequencing projects in a number of eukaryotes allows comparative analysis of orthologs, which can aid in identifying evolutionary constraints on protein structure and function. Nucleoside transporters (NTs) are present in a diverse array of organisms and previous studies have suggested that there is low protein sequence similarity but conserved structure in invertebrate and vertebrate NT orthologs. In addition, most taxa possess multiple NT isoforms but their respective roles in the physiology of the organism are not clear. To investigate the evolution of the structure and function of NTs, we have extended our previous studies by identifying NT orthologs in the Dipteran Anopheles gambiae and comparing these proteins to human and Drosophila melanogaster (Dm) NTs. In addition, we have functionally characterized DmENT2, one of three putative D. melanogaster ENTs that we have previously described. DmENT2 has broad substrate specificity, is insensitive to standard nucleoside transport inhibitors and is expressed in the digestive tract of late stage embryos based on in situ hybridization. DmENT1 and DmENT2 are expressed in most stages during development with the exception of early embryogenesis suggesting specific physiological roles for each isoform. These data represent the first complete genomic analysis of Dipteran NTs and the first report of the functional characterization of any Dipteran NT.

Functional characterization of human brown adipose tissue metabolism

2020 ◽  
Vol 477 (7) ◽  
pp. 1261-1286 ◽  
Author(s):  
Marie Anne Richard ◽  
Hannah Pallubinsky ◽  
Denis P. Blondin
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Functional Characterization ◽  
Human Infants ◽  
Positron Emission ◽  
Brown Adipose ◽  
Treatment Of Obesity ◽  
And Function

Brown adipose tissue (BAT) has long been described according to its histological features as a multilocular, lipid-containing tissue, light brown in color, that is also responsive to the cold and found especially in hibernating mammals and human infants. Its presence in both hibernators and human infants, combined with its function as a heat-generating organ, raised many questions about its role in humans. Early characterizations of the tissue in humans focused on its progressive atrophy with age and its apparent importance for cold-exposed workers. However, the use of positron emission tomography (PET) with the glucose tracer [18F]fluorodeoxyglucose ([18F]FDG) made it possible to begin characterizing the possible function of BAT in adult humans, and whether it could play a role in the prevention or treatment of obesity and type 2 diabetes (T2D). This review focuses on the in vivo functional characterization of human BAT, the methodological approaches applied to examine these features and addresses critical gaps that remain in moving the field forward. Specifically, we describe the anatomical and biomolecular features of human BAT, the modalities and applications of non-invasive tools such as PET and magnetic resonance imaging coupled with spectroscopy (MRI/MRS) to study BAT morphology and function in vivo, and finally describe the functional characteristics of human BAT that have only been possible through the development and application of such tools.

scholarly journals A Rubisco-binding protein is required for normal pyrenoid number and starch sheath morphology inChlamydomonas reinhardtii

2019 ◽  
Vol 116 (37) ◽  
pp. 18445-18454 ◽  
Author(s):  
Alan K. Itakura ◽  
Kher Xing Chan ◽  
Nicky Atkinson ◽  
Leif Pallesen ◽  
Lianyong Wang ◽  
...  
Keyword(s):  
Surface Area ◽  
Structure And Function ◽  
Binding Motif ◽  
Starch Granules ◽  
Wild Type ◽  
Bisphosphate Carboxylase ◽  
Biophysical Mechanism ◽  
Mechanism Function ◽  
And Function

A phase-separated, liquid-like organelle called the pyrenoid mediates CO2fixation in the chloroplasts of nearly all eukaryotic algae. While most algae have 1 pyrenoid per chloroplast, here we describe a mutant in the model algaChlamydomonasthat has on average 10 pyrenoids per chloroplast. Characterization of the mutant leads us to propose a model where multiple pyrenoids are favored by an increase in the surface area of the starch sheath that surrounds and binds to the liquid-like pyrenoid matrix. We find that the mutant’s phenotypes are due to disruption of a gene, which we call StArch Granules Abnormal 1 (SAGA1) because starch sheath granules, or plates, in mutants lacking SAGA1 are more elongated and thinner than those of wild type. SAGA1 contains a starch binding motif, suggesting that it may directly regulate starch sheath morphology. SAGA1 localizes to multiple puncta and streaks in the pyrenoid and physically interacts with the small and large subunits of the carbon-fixing enzyme Rubisco (ribulose-1,5-bisphosphate carboxylase/oxygenase), a major component of the liquid-like pyrenoid matrix. Our findings suggest a biophysical mechanism by which starch sheath morphology affects pyrenoid number and CO2-concentrating mechanism function, advancing our understanding of the structure and function of this biogeochemically important organelle. More broadly, we propose that the number of phase-separated organelles can be regulated by imposing constraints on their surface area.

scholarly journals Characterization of splice variants of human caspase-activated DNase with CIDE-N structure and function

FEBS Letters ◽  
2004 ◽  
Vol 566 (1-3) ◽  
pp. 234-240 ◽  
Author(s):  
José R. Bayascas ◽  
Vı́ctor J. Yuste ◽  
Carme Solé ◽  
Isabel Sánchez-López ◽  
Miquel F. Segura ◽  
...  
Keyword(s):  
Splice Variants ◽  
Structure And Function ◽  
Caspase Activated Dnase ◽  
And Function ◽  
Human Caspase

scholarly journals Structural Features of a Bacteroidetes-Affiliated Cellulase Linked with a Polysaccharide Utilization Locus

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
A.E. Naas ◽  
A.K. MacKenzie ◽  
B. Dalhus ◽  
V.G.H. Eijsink ◽  
P.B. Pope
Keyword(s):  
Active Site ◽  
Three Dimensional ◽  
Structural Features ◽  
Structure And Function ◽  
Dimensional Structure ◽  
Active Site Cleft ◽  
Polysaccharide Utilization Locus ◽  
And Function ◽  
Rumen Metagenome

Abstract Previous gene-centric analysis of a cow rumen metagenome revealed the first potentially cellulolytic polysaccharide utilization locus, of which the main catalytic enzyme (AC2aCel5A) was identified as a glycoside hydrolase (GH) family 5 endo-cellulase. Here we present the 1.8 Å three-dimensional structure of AC2aCel5A and characterization of its enzymatic activities. The enzyme possesses the archetypical (β/α)8-barrel found throughout the GH5 family and contains the two strictly conserved catalytic glutamates located at the C-terminal ends of β-strands 4 and 7. The enzyme is active on insoluble cellulose and acts exclusively on linear β-(1,4)-linked glucans. Co-crystallization of a catalytically inactive mutant with substrate yielded a 2.4 Å structure showing cellotriose bound in the −3 to −1 subsites. Additional electron density was observed between Trp178 and Trp254, two residues that form a hydrophobic “clamp”, potentially interacting with sugars at the +1 and +2 subsites. The enzyme’s active-site cleft was narrower compared to the closest structural relatives, which in contrast to AC2aCel5A, are also active on xylans, mannans and/or xyloglucans. Interestingly, the structure and function of this enzyme seem adapted to less-substituted substrates such as cellulose, presumably due to the insufficient space to accommodate the side-chains of branched glucans in the active-site cleft.

scholarly journals Conservation of dishevelled structure and function between flies and mice: isolation and characterization of Dvl2

1996 ◽  
Vol 58 (1-2) ◽  
pp. 15-26 ◽  
Author(s):  
J. Klingensmith ◽  
Y. Yang ◽  
J.D. Axelrod ◽  
D.R. Beier ◽  
N. Perrimon ◽  
...  
Keyword(s):  
Structure And Function ◽  
Isolation And Characterization ◽  
And Function

Biophysical methods toolbox to study ABC exporter structure and function

2017 ◽  
Vol 398 (2) ◽  
pp. 229-235
Author(s):  
Thomas Marcellino ◽  
Vasundara Srinivasan
Keyword(s):  
Membrane Proteins ◽  
Abc Transporter ◽  
Integrated Approach ◽  
Structure And Function ◽  
Dynamic Membrane ◽  
Biophysical Characterization ◽  
Intermediate States ◽  
And Function

Abstract ABC exporters are highly dynamic membrane proteins that span a huge spectrum of different conformations. A detailed integrated approach of cellular, biochemical and biophysical characterization of these ‘open’, ‘closed’ and other intermediate states is central to understanding their function. Almost 40 years after the discovery of the first ABC transporter, thanks to the enormous development in methodologies, a picture is slowly emerging to visualize how these fascinating molecules transport their substrates. This mini review summarizes some of the biophysical tools that have made a major impact in understanding the function of the ABC exporters.

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