Characterization of the structure and function of site- directed mutants of human gamma-interferon

Cytokine ◽  
1989 ◽  
Vol 1 (1) ◽  
pp. 77
Keyword(s):  
Structure And Function ◽  
Gamma Interferon ◽  
And Function

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.

scholarly journals Capillary-associated microglia regulate vascular structure and function through PANX1-P2RY12 coupling in mice

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Kanchan Bisht ◽  
Kenneth A. Okojie ◽  
Kaushik Sharma ◽  
Dennis H. Lentferink ◽  
Yu-Yo Sun ◽  
...  
Keyword(s):  
Myeloid Cell ◽  
Structure And Function ◽  
Pannexin 1 ◽  
Vascular Physiology ◽  
Blood Flow Increase ◽  
Bona Fide ◽  
Spatio Temporal ◽  
And Function ◽  
The Brain

AbstractMicroglia are brain-resident immune cells with a repertoire of functions in the brain. However, the extent of their interactions with the vasculature and potential regulation of vascular physiology has been insufficiently explored. Here, we document interactions between ramified CX3CR1 + myeloid cell somata and brain capillaries. We confirm that these cells are bona fide microglia by molecular, morphological and ultrastructural approaches. Then, we give a detailed spatio-temporal characterization of these capillary-associated microglia (CAMs) comparing them with parenchymal microglia (PCMs) in their morphological activities including during microglial depletion and repopulation. Molecularly, we identify P2RY12 receptors as a regulator of CAM interactions under the control of released purines from pannexin 1 (PANX1) channels. Furthermore, microglial elimination triggered capillary dilation, blood flow increase, and impaired vasodilation that were recapitulated in P2RY12−/− and PANX1−/− mice suggesting purines released through PANX1 channels play important roles in activating microglial P2RY12 receptors to regulate neurovascular structure and function.

scholarly journals Susceptibility of protein therapeutics to spontaneous chemical modifications by oxidation, cyclization, and elimination reactions

Amino Acids ◽  
2019 ◽  
Vol 51 (10-12) ◽  
pp. 1409-1431 ◽  
Author(s):  
Luigi Grassi ◽  
Chiara Cabrele
Keyword(s):  
Small Molecules ◽  
Three Dimensional ◽  
Drug Market ◽  
Structure And Function ◽  
Dimensional Structure ◽  
Chemical Modifications ◽  
Small Molecule Drugs ◽  
And Function ◽  
The Impact

Abstract Peptides and proteins are preponderantly emerging in the drug market, as shown by the increasing number of biopharmaceutics already approved or under development. Biomolecules like recombinant monoclonal antibodies have high therapeutic efficacy and offer a valuable alternative to small-molecule drugs. However, due to their complex three-dimensional structure and the presence of many functional groups, the occurrence of spontaneous conformational and chemical changes is much higher for peptides and proteins than for small molecules. The characterization of biotherapeutics with modern and sophisticated analytical methods has revealed the presence of contaminants that mainly arise from oxidation- and elimination-prone amino-acid side chains. This review focuses on protein chemical modifications that may take place during storage due to (1) oxidation (methionine, cysteine, histidine, tyrosine, tryptophan, and phenylalanine), (2) intra- and inter-residue cyclization (aspartic and glutamic acid, asparagine, glutamine, N-terminal dipeptidyl motifs), and (3) β-elimination (serine, threonine, cysteine, cystine) reactions. It also includes some examples of the impact of such modifications on protein structure and function.

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