scholarly journals Biochemical and structural characterization of a novel arginine kinase from the spider Polybetes pythagoricus

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3787 ◽  
Author(s):  
Aldana Laino ◽  
Alonso A. Lopez-Zavala ◽  
Karina D. Garcia-Orozco ◽  
Jesus S. Carrasco-Miranda ◽  
Marianela Santana ◽  
...  
Keyword(s):  
Active Site ◽  
Energy Supply ◽  
Kinetic Constant ◽  
Arginine Kinase ◽  
Terrestrial Ecosystems ◽  
Menten Kinetic ◽  
Guanidino Group ◽  
Biomedical Interest ◽  
Polybetes Pythagoricus

Energy buffering systems are key for homeostasis during variations in energy supply. Spiders are the most important predators for insects and therefore key in terrestrial ecosystems. From biomedical interest, spiders are important for their venoms and as a source of potent allergens, such as arginine kinase (AK, EC 2.7.3.3). AK is an enzyme crucial for energy metabolism, keeping the pool of phosphagens in invertebrates, and also an allergen for humans. In this work, we studied AK from the Argentininan spider Polybetes pythagoricus (PpAK), from its complementary DNA to the crystal structure. The PpAK cDNA from muscle was cloned, and it is comprised of 1068 nucleotides that encode a 384-amino acids protein, similar to other invertebrate AKs. The apparent Michaelis-Menten kinetic constant (Km) was 1.7 mM with a kcat of 75 s−1. Two crystal structures are presented, the apoPvAK and PpAK bound to arginine, both in the open conformation with the active site lid (residues 310–320) completely disordered. The guanidino group binding site in the apo structure appears to be organized to accept the arginine substrate. Finally, these results contribute to knowledge of mechanistic details of the function of arginine kinase.

scholarly journals Characterization of the Active Site Structures of Arginine Kinase-Substrate Complexes

1974 ◽  
Vol 249 (18) ◽  
pp. 5741-5748 ◽  
Author(s):  
Daniel H. Buttlaire ◽  
Mildred Cohn
Keyword(s):  
Active Site ◽  
Arginine Kinase ◽  
Kinase Substrate

scholarly journals Generation and Characterization of a Mutant of Influenza A Virus Selected with the Neuraminidase Inhibitor BCX-140

1998 ◽  
Vol 42 (4) ◽  
pp. 801-807 ◽  
Author(s):  
Shanta Bantia ◽  
Anita A. Ghate ◽  
Sandya L. Ananth ◽  
Y. Sudhakar Babu ◽  
Gillian M. Air ◽  
...  
Keyword(s):  
Sialic Acid ◽  
Binding Site ◽  
Active Site ◽  
Influenza A ◽  
Neuraminidase Inhibitor ◽  
Active Site Residues ◽  
Binding Studies ◽  
Drug Induced ◽  
Guanidino Group

ABSTRACT Influenza neuraminidase (NA) plays an important role in viral replication, and characterization of viruses resistant to NA inhibitors will help elucidate the role of active-site residues. This information will assist in designing better inhibitors targeted to essential active-site residues that cannot generate drug-resistant mutations. In the present study we used the benzoic acid-based inhibitor BCX-140 to select and characterize resistant viruses. BCX-140 binds to the NA active site in an orientation that is opposite that of a sialic acid-based compound, 4-guanidino-2,4-dideoxy-2,3-dehydro-N-acetylneuraminic acid (GANA). Thus, the guanidino group of BCX-140 binds to Glu-276, whereas in GANA the guanidino group binds to Glu-119. We passaged influenza A/Singapore/1/57 (H2N2) in Madin-Darby canine kidney cells in the presence of BCX-140, and virus resistant to this inhibitor was selected after six passages. The NA of this mutant was still sensitive to inhibition by BCX-140. However, the mutant virus was resistant to BCX-140 in plaque and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays. Sequence analysis of hemagglutinin (HA) and NA genes revealed changes in both, although none were in the active site of the NA. Depending on the method of selection of the resistant virus, two types of changes associated with the sialic acid binding site were seen in the HA. One is a change in HA1 of Ala-133 to Thr, a residue close to the binding site, while the other change was Arg-132 of HA1 to Gln, which in HA1 of serotype H3 is a sialic acid contact (Asn-137). Binding studies revealed that both types of resistant viruses had reduced receptor binding affinity compared to that of the wild type. Thus, resistance to BCX-140 was generated by modifying the HA. NA active-site residue 276 may be essential for activity, and thus, it cannot be changed to generate resistance. However, drug-induced changes in the HA can result in a virus that is less dependent on NA activity for growth in cells and, hence, resistant to NA inhibitors.

Characterization of an Abnormal Antithrombin (Milano 2) with Defective Thrombin Binding

1986 ◽  
Vol 56 (03) ◽  
pp. 349-352 ◽  
Author(s):  
A Tripodi ◽  
A Krachmalnicoff ◽  
P M Mannucci
Keyword(s):  
Venous Thromboembolism ◽  
Active Site ◽  
Inhibitory Activity ◽  
Antithrombin Iii ◽  
Factor Xa ◽  
Molecular Defect ◽  
Affinity Adsorption ◽  
Italian Family ◽  
Crossed Immunoelectrophoresis

SummaryFour members of an Italian family (two with histories of venous thromboembolism) had a qualitative defect of antithrombin III reflected by normal antigen concentrations and halfnormal antithrombin activity with or without heparin. Anti-factor Xa activities were consistently borderline low (about 70% of normal). For the propositus’ plasma and serum the patterns of antithrombin III in crossed-immunoelectrophoresis with or without heparin were indistinguishable from those of normal plasma or serum. A normal affinity of antithrombin III for heparin was documented by heparin-sepharose chromatography. Affinity adsorption of the propositus’ plasma to human α-thrombin immobilized on sepharose beads revealed defective binding of the anti thrombin III to thrombin-sepharose. Hence the molecular defect of this variant appears to be at the active site responsible for binding and neutralizing thrombin, thus accounting for the low thrombin inhibitory activity.

Computer Simulation of Amperometric Biosensor Response to Mixtures of Compounds

2002 ◽  
Vol 7 (2) ◽  
pp. 3-14 ◽  
Author(s):  
R. Baronas ◽  
J. Christensen ◽  
F. Ivanauskas ◽  
J. Kulys
Keyword(s):  
Computer Simulation ◽  
Enzymatic Reaction ◽  
Diffusion Equations ◽  
Response Data ◽  
Finite Difference Technique ◽  
Stationary Diffusion ◽  
Biosensor Array ◽  
Menten Kinetic ◽  
Biosensor Response

A mathematical model of amperometric biosensors has been developed. The model bases on non-stationary diffusion equations containing a non-linear term related to Michaelis-Menten kinetic of the enzymatic reaction. The model describes the biosensor response to mixtures of multiple compounds in two regimes of analysis: batch and flow injection. Using computer simulation, large amount of biosensor response data were synthesised for calibration of a biosensor array to be used for characterization of wastewater. The computer simulation was carried out using the finite difference technique.

scholarly journals Sustainability Investigation of Vehicles’ CO2 Emission in Hungary

2021 ◽  
Vol 13 (15) ◽  
pp. 8237
Author(s):  
István Árpád ◽  
Judit T. Kiss ◽  
Gábor Bellér ◽  
Dénes Kocsis
Keyword(s):  
Energy Efficiency ◽  
Co2 Emissions ◽  
Energy Supply ◽  
Internal Combustion Engines ◽  
Combustion Engines ◽  
The European Union ◽  
New Approach ◽  
Technology System ◽  
Low Co2

The regulation of vehicular CO2 emissions determines the permissible emissions of vehicles in units of g CO2/km. However, these values only partially provide adequate information because they characterize only the vehicle but not the emission of the associated energy supply technology system. The energy needed for the motion of vehicles is generated in several ways by the energy industry, depending on how the vehicles are driven. These methods of energy generation consist of different series of energy source conversions, where the last technological step is the vehicle itself, and the result is the motion. In addition, sustainability characterization of vehicles cannot be determined by the vehicle’s CO2 emissions alone because it is a more complex notion. The new approach investigates the entire energy technology system associated with the generation of motion, which of course includes the vehicle. The total CO2 emissions and the resulting energy efficiency have been determined. For this, it was necessary to systematize (collect) the energy supply technology lines of the vehicles. The emission results are not given in g CO2/km but in g CO2/J, which is defined in the paper. This new method is complementary to the European Union regulative one, but it allows more complex evaluations of sustainability. The calculations were performed based on Hungarian data. Finally, using the resulting energy efficiency values, the emission results were evaluated by constructing a sustainability matrix similar to the risk matrix. If only the vehicle is investigated, low CO2 emissions can be achieved with vehicles using internal combustion engines. However, taking into consideration present technologies, in terms of sustainability, the spread of electric-only vehicles using renewable energies can result in improvement in the future. This proposal was supported by the combined analysis of the energy-specific CO2 emissions and the energy efficiency of vehicles with different power-driven systems.

scholarly journals Structural Characterization of Two CO Molecules Bound to the Nitrogenase Active Site

2020 ◽  
Author(s):  
Trixia M. Buscagan ◽  
Kathryn A. Perez ◽  
Ailiena O. Maggiolo ◽  
Douglas C. Rees ◽  
Thomas Spatzal
Keyword(s):  
Structural Characterization ◽  
Active Site

scholarly journals Characterization of Light-Induced, Short-Lived Interacting Radicals in the Active Site of Flavoprotein Ferredoxin-NADP+ Oxidoreductase

2021 ◽  
Vol 143 (7) ◽  
pp. 2757-2768
Author(s):  
Bo Zhuang ◽  
Daisuke Seo ◽  
Alexey Aleksandrov ◽  
Marten H. Vos
Keyword(s):  
Active Site

scholarly journals Characterization of two azurphil granule proteases with active-site homology to neutrophil elastase.

1990 ◽  
Vol 265 (4) ◽  
pp. 2038-2041
Author(s):  
C G Wilde ◽  
J L Snable ◽  
J E Griffith ◽  
R W Scott
Keyword(s):  
Active Site ◽  
Neutrophil Elastase
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