The catalytic activity of GSTM1 in vitro is independent of MAPK8

2021 ◽  
Vol 14 ◽  
Author(s):  
Shannon Robin ◽  
Khalil Ben-Hassine ◽  
Simona Jurkovic Mlakar ◽  
Vid Mlakar ◽  
Marc Ansari ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
In Silico ◽  
Enzyme Assay ◽  
Amino Acid Residues ◽  
Protein Protein Interaction ◽  
Binding Interface ◽  
Mitogen Activated Protein ◽  
Apoptosis Pathways ◽  
Glutathione S Transferases

Background: Glutathione S-transferases (GSTs) are phase II metabolic enzymes crucial for the metabolism of electrophilic drugs. Additionally, several GST isoforms are involved in protein-protein interaction with mitogen-activated protein kinases (MAPKs), modulating apoptosis pathways. Methods: To assess the potential change of enzymatic activity, we performed a GST enzyme assay with human recombinant GSTM1 in the presence and absence of MAPK8. Recently, GSTM1 has been demonstrated to interact with MAPK8 both in silico and in vitro. The binding interface predicted in silico comprised amino acid residues present on the surface of the protein and a few were deep in the active site of the protein. Results: The experiment demonstrated that the GSTM1 activity was conserved even in the presence of MAPK8 in the assay. Conclusion: Thus, this interaction with MAPK8 may potentially cause an alteration of the catalytic activity of GSTM1.

scholarly journals Mapping the Contact Sites of the Escherichia coli Division-Initiating Proteins FtsZ and ZapA by BAMG Cross-Linking and Site-Directed Mutagenesis

2018 ◽  
Vol 19 (10) ◽  
pp. 2928 ◽  
Author(s):  
Winfried Roseboom ◽  
Madhvi Nazir ◽  
Nils Meiresonne ◽  
Tamimount Mohammadi ◽  
Jolanda Verheul ◽  
...  
Keyword(s):  
Site Directed Mutagenesis ◽  
Cross Linking ◽  
Directed Mutagenesis ◽  
Amino Acid Residues ◽  
Binding Interface ◽  
Tetrameric Structure ◽  
Z Ring ◽  
Cross Links ◽  
Chemical Cross Linking

Cell division in bacteria is initiated by the polymerization of FtsZ at midcell in a ring-like structure called the Z-ring. ZapA and other proteins assist Z-ring formation and ZapA binds ZapB, which senses the presence of the nucleoids. The FtsZ–ZapA binding interface was analyzed by chemical cross-linking mass spectrometry (CXMS) under in vitro FtsZ-polymerizing conditions in the presence of GTP. Amino acids residue K42 from ZapA was cross-linked to amino acid residues K51 and K66 from FtsZ, close to the interphase between FtsZ molecules in protofilaments. Five different cross-links confirmed the tetrameric structure of ZapA. A number of FtsZ cross-links suggests that its C-terminal domain of 55 residues, thought to be largely disordered, has a limited freedom to move in space. Site-directed mutagenesis of ZapA reveals an interaction site in the globular head of the protein close to K42. Using the information on the cross-links and the mutants that lost the ability to interact with FtsZ, a model of the FtsZ protofilament–ZapA tetramer complex was obtained by information-driven docking with the HADDOCK2.2 webserver.

scholarly journals Quinazolin-4-one derivatives lacking toxicity-producing attributes as glucokinase activators: design, synthesis, molecular docking, and in-silico ADMET prediction

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Saurabh C. Khadse ◽  
Nikhil D. Amnerkar ◽  
Manasi U. Dave ◽  
Deepak K. Lokwani ◽  
Ravindra R. Patil ◽  
...  
Keyword(s):  
Molecular Docking ◽  
In Silico ◽  
Enzyme Assay ◽  
Binding Free Energy ◽  
Docking Studies ◽  
Oral Glucose ◽  
Substitution Pattern ◽  
Glucokinase Activators ◽  
In Silico Admet

Abstract Background A small library of quinazolin-4-one clubbed thiazole acetates/acetamides lacking toxicity-producing functionalities was designed, synthesized, and evaluated for antidiabetic potential as glucokinase activators (GKA). Molecular docking studies were done in the allosteric site of the human glucokinase (PDB ID: 1V4S) enzyme to assess the binding mode and interactions of synthesized hits for best-fit conformations. All the compounds were evaluated by in vitro enzymatic assay for GK activation. Results Data showed that compounds 3 (EC50 = 632 nM) and 4 (EC50 = 516 nM) showed maximum GK activation compared to the standards RO-281675 and piragliatin. Based on the results of the in vitro enzyme assay, docking studies, and substitution pattern, selected compounds were tested for their glucose-lowering effect in vivo by oral glucose tolerance test (OGTT) in normal rats. Compounds 3 (133 mg/dL) and 4 (135 mg/dL) exhibited prominent activity by lowering the glucose level to almost normal, eliciting the results in parallel to enzyme assay and docking studies. Binding free energy, hydrogen bonding, and π–π interactions of most active quinazolin-4-one derivatives 3 and 4 with key amino acid residues of the 1V4S enzyme were studied precisely. Preliminary in-silico absorption, distribution, metabolism, excretion, and toxicity (ADMET) prediction was carried out using SwissADME and PreADMET online software which revealed that all the compounds have the potential to become orally active antidiabetic agents as they obeyed Lipinski's rule of five. Conclusion The results revealed that the designed lead could be significant for the strategic design of safe, effective, and orally bioavailable quinazolinone derivatives as glucokinase activators.

scholarly journals Identification of a ubiquitin-binding interface using Rosetta and DEER

2018 ◽  
Vol 115 (3) ◽  
pp. 525-530 ◽  
Author(s):  
Maxx H. Tessmer ◽  
David M. Anderson ◽  
Adam M. Pickrum ◽  
Molly O. Riegert ◽  
Rocco Moretti ◽  
...  
Keyword(s):  
Enzymatic Activity ◽  
Tissue Injury ◽  
Target Cells ◽  
Biological Assays ◽  
X Ray Crystallography ◽  
Protein Protein Interaction ◽  
Binding Interface ◽  
Ubiquitin Binding ◽  
Double Electron Electron Resonance

ExoU is a type III-secreted cytotoxin expressing A2 phospholipase activity when injected into eukaryotic target cells by the bacterium Pseudomonas aeruginosa. The enzymatic activity of ExoU is undetectable in vitro unless ubiquitin, a required cofactor, is added to the reaction. The role of ubiquitin in facilitating ExoU enzymatic activity is poorly understood but of significance for designing inhibitors to prevent tissue injury during infections with strains of P. aeruginosa producing this toxin. Most ubiquitin-binding proteins, including ExoU, demonstrate a low (micromolar) affinity for monoubiquitin (monoUb). Additionally, ExoU is a large and dynamic protein, limiting the applicability of traditional structural techniques such as NMR and X-ray crystallography to define this protein–protein interaction. Recent advancements in computational methods, however, have allowed high-resolution protein modeling using sparse data. In this study, we combine double electron–electron resonance (DEER) spectroscopy and Rosetta modeling to identify potential binding interfaces of ExoU and monoUb. The lowest-energy scoring model was tested using biochemical, biophysical, and biological techniques. To verify the binding interface, Rosetta was used to design a panel of mutations to modulate binding, including one variant with enhanced binding affinity. Our analyses show the utility of computational modeling when combined with sensitive biological assays and biophysical approaches that are exquisitely suited for large dynamic proteins.

scholarly journals Methods for addressing the protein-protein interaction between histone deacetylase 6 and ubiquitin

2017 ◽  
Author(s):  
Carolina dos S. Passos ◽  
Nathalie Deschamps ◽  
Yun Choi ◽  
Robert E. Cohen ◽  
Remo Perozzo ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Stress Response ◽  
Small Molecules ◽  
Histone Deacetylase ◽  
Protein Interaction ◽  
Potential Role ◽  
Histone Deacetylase 6 ◽  
Protein Protein Interaction ◽  
Binding Function

AbstractHistone deacetylase 6 (HDAC6) is a cytoplasmic HDAC isoform able to remove acetyl groups from cellular substrates such as α-tubulin. In addition to the two deacetylase domains, HDAC6 has a C-terminal zinc-finger ubiquitin (Ub)-binding domain (ZnF-UBP) able to recognize free Ub. HDAC6-Ub interaction is thought to function in regulating the elimination of misfolded proteins during stress response through the aggresome pathway. Small molecules inhibiting deacetylation by HDAC6 were shown to reduce aggresomes, but the interplay between HDAC6 catalytic activity and Ub-binding function is not fully understood. Here we describe two methods to measure the HDAC6-Ub interaction in vitro using full-length HDAC6. Both methods were effective for screening inhibitors of the HDAC6-Ub protein-protein interaction independently of the catalytic activity. Our results suggest a potential role for the HDAC6 deacetylase domains in modulating HDAC6-Ub interaction. This new aspect of HDAC6 regulation can be targeted to address the roles of HDAC6-Ub interaction in normal and disease conditions.

Determination of primary sequence specificity of Arabidopsis MAPKs MPK3 and MPK6 leads to identification of new substrates

2012 ◽  
Vol 446 (2) ◽  
pp. 271-278 ◽  
Author(s):  
Carolin Sörensson ◽  
Marit Lenman ◽  
Jenny Veide-Vilg ◽  
Simone Schopper ◽  
Thomas Ljungdahl ◽  
...  
Keyword(s):  
Phosphorylation Site ◽  
Dependent Manner ◽  
Sequence Specificity ◽  
Amino Acid Residues ◽  
Primary Sequence ◽  
In Planta ◽  
Mitogen Activated Protein ◽  
Arabidopsis Proteins ◽  
Mutant Forms

MAPKs (mitogen-activated protein kinases) are signalling components highly conserved among eukaryotes. Their diverse biological functions include cellular differentiation and responses to different extracellular stress stimuli. Although some substrates of MAPKs have been identified in plants, no information is available about whether amino acids in the primary sequence other than proline-directed phosphorylation (pS-P) contribute to kinase specificity towards substrates. In the present study, we used a random positional peptide library to search for consensus phosphorylation sequences for Arabidopsis MAPKs MPK3 and MPK6. These experiments indicated a preference towards the sequence L/P-P/X-S-P-R/K for both kinases. After bioinformatic processing, a number of novel candidate MAPK substrates were predicted and subsequently confirmed by in vitro kinase assays using bacterially expressed native Arabidopsis proteins as substrates. MPK3 and MPK6 phosphorylated all proteins tested more efficiently than did another MAPK, MPK4. These results indicate that the amino acid residues in the primary sequence surrounding the phosphorylation site of Arabidopsis MAPK substrates can contribute to MAPK specificity. Further characterization of one of these new substrates confirmed that At1g80180.1 was phosphorylated in planta in a MAPK-dependent manner. Phenotypic analyses of Arabidopsis expressing phosphorylation site mutant forms of At1g80180.1 showed clustered stomata and higher stomatal index in cotyledons expressing the phosphomimetic form of At1g80180.1, providing a link between this new MAPK substrate and the defined role for MPK3 and MPK6 in stomatal patterning.

scholarly journals Protein-Protein Interaction Detection: Methods and Analysis

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
V. Srinivasa Rao ◽  
K. Srinivas ◽  
G. N. Sujini ◽  
G. N. Sunand Kumar
Keyword(s):  
Protein Interaction ◽  
Protein Function ◽  
In Silico ◽  
Affinity Purification ◽  
Phylogenetic Profile ◽  
Detection Methods ◽  
Protein Protein Interaction ◽  
Interaction Detection

Protein-protein interaction plays key role in predicting the protein function of target protein and drug ability of molecules. The majority of genes and proteins realize resulting phenotype functions as a set of interactions. The in vitro and in vivo methods like affinity purification, Y2H (yeast 2 hybrid), TAP (tandem affinity purification), and so forth have their own limitations like cost, time, and so forth, and the resultant data sets are noisy and have more false positives to annotate the function of drug molecules. Thus, in silico methods which include sequence-based approaches, structure-based approaches, chromosome proximity, gene fusion, in silico 2 hybrid, phylogenetic tree, phylogenetic profile, and gene expression-based approaches were developed. Elucidation of protein interaction networks also contributes greatly to the analysis of signal transduction pathways. Recent developments have also led to the construction of networks having all the protein-protein interactions using computational methods for signaling pathways and protein complex identification in specific diseases.

scholarly journals Chemical Modifications of PhTX-I Myotoxin fromPorthidium hyoproraSnake Venom: Effects on Structural, Enzymatic, and Pharmacological Properties

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Salomón Huancahuire-Vega ◽  
Daniel H. A. Corrêa ◽  
Luciana M. Hollanda ◽  
Marcelo Lancellotti ◽  
Carlos H. I. Ramos ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Critical Role ◽  
High Catalytic Activity ◽  
Pharmacological Properties ◽  
Amino Acid Residues ◽  
Chemical Modifications ◽  
Specific Amino Acid ◽  
Catalytic Sites

We recently described the isolation of a basic PLA2(PhTX-I) fromPorthidium hyoprorasnake venom. This toxin exhibits high catalytic activity, inducesin vivomyotoxicity, moderates footpad edema, and causesin vitroneuromuscular blockade. Here, we describe the chemical modifications of specific amino acid residues (His, Tyr, Lys, and Trp), performed in PhTX-I, to study their effects on the structural, enzymatic, and pharmacological properties of this myotoxin. After chemical treatment, a single His, 4 Tyr, 7 Lys, and one Trp residues were modified. The secondary structure of the protein remained unchanged as measured by circular dichroism; however other results indicated the critical role played by Lys and Tyr residues in myotoxic, neurotoxic activities and mainly in the cytotoxicity displayed by PhTX-I. His residue and therefore catalytic activity of PhTX-I are relevant for edematogenic, neurotoxic, and myotoxic effects, but not for its cytotoxic activity. This dissociation observed between enzymatic activity and some pharmacological effects suggests that other molecular regions distinct from the catalytic site may also play a role in the toxic activities exerted by this myotoxin. Our observations supported the hypothesis that both the catalytic sites as the hypothetical pharmacological sites are relevant to the pharmacological profile of PhTX-I.

scholarly journals In Silico Approaches to Identify Polyphenol Compounds as α-Glucosidase and α-Amylase Inhibitors against Type-II Diabetes

Biomolecules ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1877
Author(s):  
Jirawat Riyaphan ◽  
Dinh-Chuong Pham ◽  
Max K. Leong ◽  
Ching-Feng Weng
Keyword(s):  
Natural Products ◽  
In Silico ◽  
Type Ii Diabetes ◽  
Postprandial Glucose ◽  
Type Ii Diabetes Mellitus ◽  
Type Ii ◽  
Amino Acid Residues ◽  
Discovery Studio

Type-II diabetes mellitus (T2DM) results from a combination of genetic and lifestyle factors, and the prevalence of T2DM is increasing worldwide. Clinically, both α-glucosidase and α-amylase enzymes inhibitors can suppress peaks of postprandial glucose with surplus adverse effects, leading to efforts devoted to urgently seeking new anti-diabetes drugs from natural sources for delayed starch digestion. This review attempts to explore 10 families e.g., Bignoniaceae, Ericaceae, Dryopteridaceae, Campanulaceae, Geraniaceae, Euphorbiaceae, Rubiaceae, Acanthaceae, Rutaceae, and Moraceae as medicinal plants, and folk and herb medicines for lowering blood glucose level, or alternative anti-diabetic natural products. Many natural products have been studied in silico, in vitro, and in vivo assays to restrain hyperglycemia. In addition, natural products, and particularly polyphenols, possess diverse structures for exploring them as inhibitors of α-glucosidase and α-amylase. Interestingly, an in silico discovery approach using natural compounds via virtual screening could directly target α-glucosidase and α-amylase enzymes through Monte Carto molecular modeling. Autodock, MOE-Dock, Biovia Discovery Studio, PyMOL, and Accelrys have been used to discover new candidates as inhibitors or activators. While docking score, binding energy (Kcal/mol), the number of hydrogen bonds, or interactions with critical amino acid residues have been taken into concerning the reliability of software for validation of enzymatic analysis, in vitro cell assay and in vivo animal tests are required to obtain leads, hits, and candidates in drug discovery and development.

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