scholarly journals NADP-Dependent Aldehyde Dehydrogenase from Archaeon Pyrobaculum sp.1860: Structural and Functional Features

Archaea ◽  
2016 ◽  
Vol 2016 ◽  
pp. 1-14
Author(s):  
Ekaterina Yu. Bezsudnova ◽  
Tatiana E. Petrova ◽  
Natalia V. Artemova ◽  
Konstantin M. Boyko ◽  
Ivan G. Shabalin ◽  
...  
Keyword(s):  
Aldehyde Dehydrogenase ◽  
Active Sites ◽  
Ternary Complex ◽  
Binary Complex ◽  
Relay Systems ◽  
Binary Complexes ◽  
Proton Relay ◽  
Functional Features

We present the functional and structural characterization of the first archaeal thermostable NADP-dependent aldehyde dehydrogenase AlDHPyr1147. In vitro, AlDHPyr1147 catalyzes the irreversible oxidation of short aliphatic aldehydes at 60–85°С, and the affinity of AlDHPyr1147 to the NADP+ at 60°С is comparable to that for mesophilic analogues at 25°С. We determined the structures of the apo form of AlDHPyr1147 (3.04 Å resolution), three binary complexes with the coenzyme (1.90, 2.06, and 2.19 Å), and the ternary complex with the coenzyme and isobutyraldehyde as a substrate (2.66 Å). The nicotinamide moiety of the coenzyme is disordered in two binary complexes, while it is ordered in the ternary complex, as well as in the binary complex obtained after additional soaking with the substrate. AlDHPyr1147 structures demonstrate the strengthening of the dimeric contact (as compared with the analogues) and the concerted conformational flexibility of catalytic Cys287 and Glu253, as well as Leu254 and the nicotinamide moiety of the coenzyme. A comparison of the active sites of AlDHPyr1147 and dehydrogenases characterized earlier suggests that proton relay systems, which were previously proposed for dehydrogenases of this family, are blocked in AlDHPyr1147, and the proton release in the latter can occur through the substrate channel.

Solid State Analysis and In-Vitro Dissolution Behavior of MeloxicamHydroxy Propyl Beta Cyclodextrin-Ethanolamines Ternary Complexes

2018 ◽  
Vol 9 (01) ◽  
Author(s):  
Jafar M. ◽  
Salahuddin M. ◽  
Kayed T. S. ◽  
Ahmad N M. ◽  
Al-Eid H. A. ◽  
...  
Keyword(s):  
Solid State ◽  
Ternary Complex ◽  
Solvent Evaporation ◽  
Ternary Complexes ◽  
Drug Dissolution ◽  
Dissolution Behavior ◽  
Binary Complex ◽  
Binary Complexes ◽  
State Analysis

The present study was aimed to improve the aqueous solubility and dissolution rate of an NSAID meloxicam by hydroxy propyl β-cyclodextrin ternary complexes employing ethanolamines. Initially, meloxicam (MLX) binary complexes with Hydroxy propyl β-Cyclodextrin (HPβCD) were formulated by kneading and solvent evaporation techniques which was followed by ternary complex preparation of selected MLX-HPβCD binary complex employing different ethanolamines by solvent evaporation method. The solvent evaporationwas used in preparing ternary complexes of MLX, because it was proved to be the best method comparatively in yielding promising binary complexes of meloxicam in the initial stage of this study. MLX formed 1:1 M stoichiometric binary and ternary inclusion complexes as demonstrated by the AL-type of phase solubility curve. An increment in the stability constant value (Kc) of MLX- HPβCD complex in the presence of ethanolamines conceded higher complexation efficiency. Solid state analysis (FTIR, TGA, and SEM studies) of ternary compounds evidenced the perfect inclusion complex formation. Ternary complexes showed significant improvement in drug dissolution compared topure MLX and MLX-HPβCD binary complex. The ternary complex containing 1:1:1 molar ratio of MLX-HPβCD-DEA exhibited 86.91% drug dissolution in 1 hour, which was significantly high in relation to ternary complexes containing mono and tri ethanolamines, and it was found to follow imperatively matrix order release mechanism. On aging studied complexes showed no significant change in physical appearance, drug content and drug dissolution attributes, which clearly shows high in-vitro stability of the complexes.

DEVELOPMENT OF BINARY AND TERNARY COMPLEX OF CEFUROXIME AXETIL WITH CYCLODEXTRIN FOR IMPROVING PHARMACEUTICAL CHARACTERISTICS

2020 ◽  
pp. 107-117
Author(s):  
SAKSHI KAUSHIK ◽  
RAVINDER VERMA ◽  
DEEPIKA PUROHIT ◽  
PARIJAT PANDEY ◽  
MANISH KUMAR ◽  
...  
Keyword(s):  
Drug Release ◽  
Ternary Complex ◽  
Cefuroxime Axetil ◽  
Ternary Complexes ◽  
In Vitro Dissolution ◽  
Taste Masking ◽  
Binary Complex ◽  
Binary And Ternary Complexes ◽  
Binary Complexes

Objective: The current research objective is systematic development and characterization of binary and ternary inclusion complexes of cefuroxime axetil with β-cyclodextrin to improve its pharmaceutical characteristics by using the kneading method. Methods: Phase solubility study was carried out using Higuchi and Connors method. Based on its result, binary complexes of cefuroxime axetil with different ratio of β-cyclodextrin were developed and characterized using differential scanning calorimeter (DSC), fourier transform infrared spectroscopy (FT-IR) and X-ray powder diffractometry (XRD). Then, binary complexes were analyzed for in vitro dissolution testing. The ternary complexes were developed using different ratio of PVP K-30 as a ternary component and evaluated for in vitro dissolution testing and in vitro taste masking. Results: Binary complex of cefuroxime axetil with β-cyclodextrin (1:1) showed better drug release than pure drug. During the development of the ternary complex, β-cyclodextrin (1:1) and 1% w/v PVP K-30 as a ternary agent resulted in an optimized ternary complex. The DSC, FT-IR and XRD studies clearly revealed the formation of binary and ternary complexes. The ternary complex showed better drug release of>85% within 30 min. in comparison to binary complex. The in vitro taste-masking study revealed the taste masking efficiency of the ternary complex of cefuroxime with β-cyclodextrin. Conclusion: The developed binary and ternary complex of cefuroxime axetil based on β-cyclodextrin with PVP K-30 showed improved in vitro dissolution rate and taste masking in comparison to pure drug. The drug release was better in ternary complexes. The present research work successfully shows the utility of binary and ternary complexes for improving pharmaceutical characteristics of cefuroxime axetil.

TrioGEF1 controls Rac- and Cdc42-dependent cell structures through the direct activation of rhoG

2000 ◽  
Vol 113 (4) ◽  
pp. 729-739 ◽  
Author(s):  
A. Blangy ◽  
E. Vignal ◽  
S. Schmidt ◽  
A. Debant ◽  
C. Gauthier-Rouviere ◽  
...  
Keyword(s):  
Rho Gtpases ◽  
Active Sites ◽  
Dominant Negative ◽  
Signaling Cascade ◽  
Microtubule Network ◽  
Cell Structures ◽  
Dependent Cell

Rho GTPases regulate the morphology of cells stimulated by extracellular ligands. Their activation is controlled by guanine exchange factors (GEF) that catalyze their binding to GTP. The multidomain Trio protein represents an emerging class of Ρ regulators that contain two GEF domains of distinct specificities. We report here the characterization of Rho signaling pathways activated by the N-terminal GEF domain of Trio (TrioD1). In fibroblasts, TrioD1 triggers the formation of particular cell structures, similar to those elicited by RhoG, a GTPase known to activate both Rac1 and Cdc42Hs. In addition, the activity of TrioD1 requires the microtubule network and relocalizes RhoG at the active sites of the plasma membrane. Using a classical in vitro exchange assay, TrioD1 displays a higher GEF activity on RhoG than on Rac1. In fibroblasts, expression of dominant negative RhoG mutants totally abolished TrioD1 signaling, whereas dominant negative Rac1 and Cdc42Hs only led to partial and complementary inhibitions. Finally, expression of a Rho Binding Domain that specifically binds RhoG(GTP) led to the complete abolition of TrioD1 signaling, which strongly supports Rac1 not being activated by TrioD1 in vivo. These data demonstrate that Trio controls a signaling cascade that activates RhoG, which in turn activates Rac1 and Cdc42Hs.

scholarly journals Binding characteristics of pro-insulin-like growth factor-II from cancer patients: binary and ternary complex formation with IGF binding proteins-1 to -6

2000 ◽  
Vol 165 (2) ◽  
pp. 253-260 ◽  
Author(s):  
JJ Bond ◽  
S Meka ◽  
RC Baxter
Keyword(s):  
Complex Formation ◽  
Ternary Complex ◽  
Binding Proteins ◽  
Ternary Complexes ◽  
Binary Complex ◽  
Igf Binding Proteins ◽  
Ternary Complex Formation ◽  
Binary Complexes ◽  
Igf Binding ◽  
Igfbp 3

Many tumours secrete IGF-II in incompletely processed precursor forms. The ability of these pro-IGF-II forms to complex with the six IGF binding proteins (IGFBPs) is poorly understood. In this study, pro-IGF-II has been extracted from the serum and tumour tissue of two patients with non-islet cell tumour hypoglycaemia. These samples were used to study binary complex formation with IGFBPs-1 to -6 using competitive IGF-II binding assays and ternary complex formation with IGFBP-3 and IGFBP-5. In each case, IGFBPs-1 to -6 showed little difference in their ability to form binary complexes with recombinant IGF-II or tumour-derived pro-IGF-II forms, when the preparations were standardised according to IGF-II immunoreactivity. As previously described, ternary complex formation by acid-labile subunit (ALS) with IGFBP-3 and pro-IGF-II was greatly decreased compared with complex formation with mature IGF-II. In contrast, ALS bound similarly to IGFBP-5 in the presence of pro-IGF-II and mature IGF-II. These studies suggest that pro-IGF-II preferentially forms binary complexes with IGFBPs, and ternary complexes with IGFBP-5, rather than ternary complexes with IGFBP-3 as seen predominantly in normal serum. This may increase the tissue availability of serum pro-IGF-II, allowing its insulin-like potential to be realised.

scholarly journals A Method for Determining the Kinetics of Small-Molecule-Induced Ubiquitination

2021 ◽  
Vol 26 (4) ◽  
pp. 547-559
Author(s):  
Ellen F. Vieux ◽  
Roman V. Agafonov ◽  
Lydia Emerson ◽  
Marta Isasa ◽  
Richard W. Deibler ◽  
...  
Keyword(s):  
Ternary Complex ◽  
Ubiquitin Proteasome System ◽  
Binary Complex ◽  
Discovery Process ◽  
Drug Discovery Process ◽  
In Vitro System ◽  
Ubiquitin Proteasome ◽  
Catalytic Rate ◽  
Kinetics Of

Recent advances in targeted protein degradation have enabled chemical hijacking of the ubiquitin–proteasome system to treat disease. The catalytic rate of cereblon (CRBN)-dependent bifunctional degradation activating compounds (BiDAC), which recruit CRBN to a chosen target protein, resulting in its ubiquitination and proteasomal degradation, is an important parameter to consider during the drug discovery process. In this work, an in vitro system was developed to measure the kinetics of BRD4 bromodomain 1 (BD1) ubiquitination by fitting an essential activator kinetic model to these data. The affinities between BiDACs, BD1, and CRBN in the binary complex, ternary complex, and full ubiquitination complex were characterized. Together, this work provides a new tool for understanding and optimizing the catalytic and thermodynamic properties of BiDACs.

Kinetic characterization of apoptotic Ras signaling through Nore1-MST1 complex formation

2017 ◽  
Vol 398 (5-6) ◽  
pp. 701-707 ◽  
Author(s):  
Agne Koturenkiene ◽  
Cihan Makbul ◽  
Christian Herrmann ◽  
Diana Constantinescu-Aruxandei
Keyword(s):  
Complex Formation ◽  
Ternary Complex ◽  
External Factors ◽  
Kinetic Constants ◽  
Ras Signaling ◽  
Kinetic Characterization ◽  
Apoptotic Signaling ◽  
First Time

Abstract Ras-mediated apoptotic signaling is expected to be mediated via Rassf-MST complexes, but the system has been poorly characterized in vitro until now. Here we demonstrate that active H-Ras, Nore1A and MST1 form a stable ternary complex in vitro without other external factors, Nore1A interacting simultaneously with H-Ras and MST1 via its RBD and SARAH domain, respectively. Moreover, our data show for the first time that the SARAH domain of Nore1A plays a role in the Nore1A binding to H-Ras. Finally, we analyze the relation between the electrostatic and hydrophobic forces and kinetic constants of the Nore1A – H-Ras complex.

scholarly journals Purification and characterization of the imidazoleglycerol-phosphate dehydratase of Saccharomyces cerevisiae from recombinant Escherichia coli

1995 ◽  
Vol 306 (2) ◽  
pp. 385-397 ◽  
Author(s):  
T R Hawkes ◽  
P G Thomas ◽  
L S Edwards ◽  
S J Rayner ◽  
K W Wilkinson ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Saccharomyces Cerevisiae ◽  
Active Sites ◽  
Active Form ◽  
Recombinant Escherichia Coli ◽  
Assay Method ◽  
Progress Curve ◽  
Low Concentrations

The HIS3+ gene of Saccharomyces cerevisiae was overexpressed in Escherichia coli and the recombinant imidazoleglycerol-phosphate dehydratase (IGPD) purified to homogeneity. Laser-desorption and electrospray m.s. indicated a molecular ion within 2 units of that expected (23833.3) on the basis of the protein sequence, with about half of the polypeptide lacking the N-terminal formylmethionine residue. IGPD initially purified as an apoprotein was catalytically inactive and mainly a trimer of M(r) 70,000. Addition of Mn2+ (but not Mg2+) caused this to assemble to an active (40 units/mg) enzyme (Mn-IGPD) comprising of 24 subunits (M(r) 573,000) and containing 1.35 +/- 0.1 Mn atoms/polypeptide subunit. An enzyme with an identical activity and metal content was also obtained when the fermenter growth medium of recombinant Escherichia coli was supplemented with MnCl2, and IGPD was purified through as Mn-IGPD rather than as the apoenzyme and assembled in vitro. Inhibition by EDTA indicated that the intrinsic Mn2+ was essential for activity. The retention of activity over time after dilution to very low concentrations of enzyme (< 20 nM) indicated that the metal remained in tight association with the protein. A novel continuous assay method was developed to facilitate the kinetic characterization of Mn-IGPD. At pH 7.0, the Km for IGP was 0.10 +/- 0.02 mM and the Ki value for inhibition by 1,2,4-triazole, 0.12 +/- 0.02 mM. In contrast with other reports, thiols had no influence on catalytic activity. The activity of Mn-IGPD varied with enzyme concentration in such a way as to suggest that it dissociates to a less active form at very low concentrations. Significant inhibition by the product, imidazole acetol phosphate, was inferred from the shape of the progress curve. Titration with, the potent competitive inhibitor, 2-hydroxy-3-(1,2,4-triazol-1-yl)propyl phosphonate indicated that Mn-IGPD contained 0.9 +/- 0.1 catalytic sites/protomer. The activity nearly doubled in the presence of high concentrations of Mn2+; the apparent Ks for stimulation was 20 microM. The basis of this effect was obscure, since there was no corresponding increase in the titre of active sites. Neither was there a discernable shift in the values of Km or Ki (above), although exogenous Mn2+ did reduce the optimum pH for kcat, from 7.2 to 6.8. On the basis of a single site/subunit, the maximum rate of catalytic turnover at 30 degrees C was 32 s-1.

scholarly journals Biochemical Characterization of Signal Peptidase I from Gram-Positive Streptococcus pneumoniae

2001 ◽  
Vol 183 (2) ◽  
pp. 621-627 ◽  
Author(s):  
Sheng-Bin Peng ◽  
Li Wang ◽  
John Moomaw ◽  
Robert B. Peery ◽  
Pei-Ming Sun ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Serine Proteases ◽  
Active Sites ◽  
Biochemical Characterization ◽  
Proteolytic Processing ◽  
Signal Peptidase ◽  
Gram Positive ◽  
Signal Peptidase I

ABSTRACT Bacterial signal peptidase I is responsible for proteolytic processing of the precursors of secreted proteins. The enzymes from gram-negative and -positive bacteria are different in structure and specificity. In this study, we have cloned, expressed, and purified the signal peptidase I of gram-positive Streptococcus pneumoniae. The precursor of streptokinase, an extracellular protein produced in pathogenic streptococci, was identified as a substrate of S. pneumoniae signal peptidase I. Phospholipids were found to stimulate the enzymatic activity. Mutagenetic analysis demonstrated that residues serine 38 and lysine 76 of S. pneumoniae signal peptidase I are critical for enzyme activity and involved in the active site to form a serine-lysine catalytic dyad, which is similar to LexA-like proteases andEscherichia coli signal peptidase I. Similar to LexA-like proteases, S. pneumoniae signal peptidase I catalyzes an intermolecular self-cleavage in vitro, and an internal cleavage site has been identified between glycine 36 and histidine 37. Sequence analysis revealed that the signal peptidase I and LexA-like proteases show sequence homology around the active sites and some common properties around the self-cleavage sites. All these data suggest that signal peptidase I and LexA-like proteases are closely related and belong to a novel class of serine proteases.

Improved Solubility and Dissolution Rate of Ketoprofen by Beta Cyclodextrin Ternary Complexes Incorporating Hydrophilic Polymers

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Mohammed Jafar ◽  
Sadath Ali ◽  
Hassan Ghonaim
Keyword(s):  
Dissolution Rate ◽  
Ternary Complex ◽  
Solvent Evaporation ◽  
Ternary Complexes ◽  
Hydrophilic Polymers ◽  
Drug Dissolution ◽  
Release Mechanism ◽  
Phase Solubility ◽  
Binary Complex ◽  
Binary Complexes

The aim of the presentstudy wasto improve the aqueous solubility and dissolution rate of a BCS Class-IIdrug,ketoprofen by β-cyclodextrin ternary complexes incorporating hydrophilic polymers polyethylene glycol 6000 (PEG6000) and polyvinyl pyrrolidone (PVP). Initially,ketoprofen (KPF)binary complexes with β-Cyclodextrin (βCD)wereformulated by physical mixing,co-grinding, and solvent evaporation methods which was followed by ternary complex formulation of selected KPF-βCD binary complex incorporatingPEG6000 and PVP.The solvent evaporation method was used in the formulation of ternary complexesof ketoprofen, sincein the beginning of this study, it was proved to be the best methodcomparatively in yielding promising binary complexes of ketoprofen.Ketoprofen formed 1:1 M stoichiometric binary and ternary inclusion complexes as demonstrated by the AL-type of phase solubility graph. An increase in the stability constant value (Kc) of KPF- βCD complex in the presence of PEG6000 and PVP conceded higher complexation competency. FTIR and SEM studies evidenced the perfect ternary inclusion complex formation. Ternary complexes showed improved drug dissolution compared with Ketoprofenalone and KPF-βCD binary complex. The ternary complex containg 1:1:2 molar ratio of KPF:βCD:PEG6000exhibited 94.24% drug dissolution in 2 hours, which was significantly high in relation to ternary complexes containg PVPand it was found to follow first order release mechanism. Complex studied for stabilityshowed no significant change in physical appearance, drug content and drug dissolution characteristic indicating high stability.

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