Unexpected Catalytic Activity of the Regulatory Protein QacR

10.26434/chemrxiv.12662003 ◽

2020 ◽

Cited By ~ 1

Author(s):

Cora Gutiérrez de Souza ◽

Lur Alonso-Cotchico ◽

Manuela Bersellini ◽

Gerard Roelfes

Keyword(s):

Catalytic Activity ◽

Multidrug Resistance ◽

Regulatory Protein ◽

Binding Pocket ◽

Computational Studies ◽

Protonation Reaction ◽

Catalytic Reactivity

Natural proteins often present binding or functional promiscuity. In biocatalysis, this promiscuity has been exploited for accessing new-to-nature reactions. Here, we report an unexpected catalytic reactivity for the regulatory protein QacR from the TetR family of multidrug resistance regulators. QacR is able to catalyze the enatioselective tandem Friedel-Crafts / enantioselective protonation reaction of indoles with alpha substituted conjugated enones with up to 40% yield and 83% ee. Mutagenesis and computational studies support the hypothesis that an acidic residue in the binding pocket of the protein is responsible for protonating the enolate intermediate.

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Study of the effect of the ligand structure on the catalytic activity of Pd@ ligand decorated halloysite: Combination of experimental and computational studies

Applied Organometallic Chemistry ◽

10.1002/aoc.4891 ◽

2019 ◽

Vol 33 (5) ◽

pp. e4891 ◽

Cited By ~ 24

Author(s):

Sevda Dehghani ◽

Samahe Sadjadi ◽

Naeimeh Bahri‐Laleh ◽

Mehdi Nekoomanesh‐Haghighi ◽

Albert Poater

Keyword(s):

Catalytic Activity ◽

Computational Studies ◽

Ligand Structure

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Suramin Targets the Conserved Ligand-Binding Pocket of Human Raf1 Kinase Inhibitory Protein

Molecules ◽

10.3390/molecules26041151 ◽

2021 ◽

Vol 26 (4) ◽

pp. 1151

Author(s):

Chenyun Guo ◽

Zhihua Wu ◽

Weiliang Lin ◽

Hao Xu ◽

Ting Chang ◽

...

Keyword(s):

Side Effects ◽

Ligand Binding ◽

Mapk Pathway ◽

Regulatory Protein ◽

Therapeutic Index ◽

Binding Pocket ◽

Biological Macromolecules ◽

Inhibitory Protein ◽

Ligand Binding Pocket ◽

Raf1 Kinase

Suramin was initially used to treat African sleeping sickness and has been clinically tested to treat human cancers and HIV infection in the recent years. However, the therapeutic index is low with numerous clinical side-effects, attributed to its diverse interactions with multiple biological macromolecules. Here, we report a novel binding target of suramin, human Raf1 kinase inhibitory protein (hRKIP), which is an important regulatory protein involved in the Ras/Raf1/MEK/ERK (MAPK) signal pathway. Biolayer interference technology showed that suramin had an intermediate affinity for binding hRKIP with a dissociation constant of 23.8 µM. Both nuclear magnetic resonance technology and molecular docking analysis revealed that suramin bound to the conserved ligand-binding pocket of hRKIP, and that residues K113, W173, and Y181 play crucial roles in hRKIP binding suramin. Furthermore, suramin treatment at 160 µM could profoundly increase the ERK phosphorylation level by around 3 times. Our results indicate that suramin binds to hRKIP and prevents hRKIP from binding with hRaf1, thus promoting the MAPK pathway. This work is beneficial to both mechanistically understanding the side-effects of suramin and efficiently improving the clinical applications of suramin.

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Congenital Lipoid Adrenal Hyperplasia: Functional Characterization of Three Novel Mutations in the STAR Gene

The Journal of Clinical Endocrinology & Metabolism ◽

10.1210/jc.2009-1176 ◽

2010 ◽

Vol 95 (3) ◽

pp. 1301-1308 ◽

Cited By ~ 20

Author(s):

Susanne Bens ◽

Angelika Mohn ◽

Bilgin Yüksel ◽

Alexandra E. Kulle ◽

Matthias Michalek ◽

...

Keyword(s):

Functional Characterization ◽

Regulatory Protein ◽

Three Dimensional ◽

Binding Pocket ◽

Adrenal Hyperplasia ◽

Turkish Patient ◽

Star Protein ◽

Sex Development ◽

Congenital Lipoid Adrenal Hyperplasia

Abstract Context: The steroidogenic acute regulatory protein (StAR) has been shown to be essential for steroidogenesis by mediating cholesterol transfer into mitochondria. Inactivating StAR mutations cause the typical clinical picture of congenital lipoid adrenal hyperplasia. Objective: The objective of the investigation was to study the functional and structural consequences of three novel StAR mutations (p.N148K in an Italian patient; p.P129fs and p.Q128R in a Turkish patient). Methods and Results: Transient in vitro expression of the mutant proteins together with P450 side-chain cleavage enzyme, adrenodoxin, and adrenodoxin reductase yielded severely diminished cholesterol conversion of the p.N148K mutant, the combined p.P129fs and p.Q128R mutant, and the p.P129fs mutant by itself. The p.Q128R mutant led to a higher cholesterol conversion than the wild-type StAR protein. As derived from three-dimensional protein modeling, the residue N148 is lining the ligand cavity of StAR. A positively charged lysine residue at position 148 disturbs the hydrophobic cluster formed by the α4-helix and the sterol binding pocket. The frame shift mutation p.P129fs truncates the StAR protein. Residue p.Q128 is situated at the surface of the molecule and is not part of any functionally characterized region of the protein. Conclusion: The mutations p.N148K and p.P129fs cause adrenal insufficiency in both cases and lead to a disorder of sex development with complete sex reversal in the 46, XY case. The mutation p.Q128R, which is not relevant for the patient’s phenotype, is the first reported variant showing a gain of function. We speculate that the substitution of hydrophilic glutamine with basic arginine at the surface of the molecule may accelerate cholesterol transfer.

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Oligomerization of 3-substituted quinolines by catalytic activity of soybean peroxidase as a wastewater treatment. Product formation and computational studies

Chemical Engineering Journal ◽

10.1016/j.cej.2019.01.184 ◽

2019 ◽

Vol 364 ◽

pp. 340-348 ◽

Cited By ~ 6

Author(s):

Neda Mashhadi ◽

Keith E. Taylor ◽

Nihar Biswas ◽

Paul Meister ◽

James W. Gauld

Keyword(s):

Wastewater Treatment ◽

Catalytic Activity ◽

Product Formation ◽

Computational Studies ◽

Soybean Peroxidase ◽

Substituted Quinolines

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A facile biomimetic catalytic activity through hydrogen atom abstraction by the secondary coordination sphere in manganese(iii) complexes

Dalton Transactions ◽

10.1039/d0dt02431g ◽

2020 ◽

Vol 49 (40) ◽

pp. 14216-14230

Author(s):

Narayan Ch. Jana ◽

Paula Brandão ◽

Antonio Frontera ◽

Anangamohan Panja

Keyword(s):

Schiff Base ◽

Catalytic Activity ◽

Hydrogen Atom ◽

Coordination Sphere ◽

Hydrogen Atom Abstraction ◽

Schiff Base Ligands ◽

Secondary Coordination Sphere ◽

Catalytic Reactivity ◽

Hydrogen Bonded

Four hydrogen bonded supramolecular manganese(iii) complexes with N3O donor Schiff base ligands and a facile biomimetic catalytic reactivity through hydrogen atom abstraction by the secondary coordination sphere have been reported.

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Synthesis, structural characterization, catalytic activity on aerobic oxidation of novel Co(II) and Fe(II) phthalocyanines and computational studies of 4-[2-(2,3-dichlorophenoxy)ethoxy]phthalonitrile

Journal of Organometallic Chemistry ◽

10.1016/j.jorganchem.2016.03.005 ◽

2016 ◽

Vol 810 ◽

pp. 25-32 ◽

Cited By ~ 13

Author(s):

Ece Tuğba Saka ◽

Serap Uzun ◽

Yasemin Çağlar

Keyword(s):

Catalytic Activity ◽

Structural Characterization ◽

Aerobic Oxidation ◽

Computational Studies

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BARP suppresses voltage-gated calcium channel activity and Ca2+-evoked exocytosis

The Journal of Cell Biology ◽

10.1083/jcb.201304101 ◽

2014 ◽

Vol 205 (2) ◽

pp. 233-249 ◽

Cited By ~ 9

Author(s):

Pascal Béguin ◽

Kazuaki Nagashima ◽

Ramasubbu N. Mahalakshmi ◽

Réjan Vigot ◽

Atsuko Matsunaga ◽

...

Keyword(s):

Subcellular Localization ◽

Functional Characterization ◽

Regulatory Protein ◽

Binding Pocket ◽

Neuroendocrine Cells ◽

Cell Surface Expression ◽

Channel Activity ◽

Interaction Domain ◽

Voltage Gated ◽

Domain I

Voltage-gated calcium channels (VGCCs) are key regulators of cell signaling and Ca2+-dependent release of neurotransmitters and hormones. Understanding the mechanisms that inactivate VGCCs to prevent intracellular Ca2+ overload and govern their specific subcellular localization is of critical importance. We report the identification and functional characterization of VGCC β-anchoring and -regulatory protein (BARP), a previously uncharacterized integral membrane glycoprotein expressed in neuroendocrine cells and neurons. BARP interacts via two cytosolic domains (I and II) with all Cavβ subunit isoforms, affecting their subcellular localization and suppressing VGCC activity. Domain I interacts at the α1 interaction domain–binding pocket in Cavβ and interferes with the association between Cavβ and Cavα1. In the absence of domain I binding, BARP can form a ternary complex with Cavα1 and Cavβ via domain II. BARP does not affect cell surface expression of Cavα1 but inhibits Ca2+ channel activity at the plasma membrane, resulting in the inhibition of Ca2+-evoked exocytosis. Thus, BARP can modulate the localization of Cavβ and its association with the Cavα1 subunit to negatively regulate VGCC activity.

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Molecular Properties of Bacterial Multidrug Transporters

Microbiology and Molecular Biology Reviews ◽

10.1128/mmbr.64.4.672-693.2000 ◽

2000 ◽

Vol 64 (4) ◽

pp. 672-693 ◽

Cited By ~ 491

Author(s):

Monique Putman ◽

Hendrik W. van Veen ◽

Wil N. Konings

Keyword(s):

Drug Transport ◽

Structural Characteristics ◽

Substrate Binding ◽

Regulatory Protein ◽

Binding Pocket ◽

Drug Binding ◽

Transport Systems ◽

Dimensional Structure ◽

Detailed Knowledge ◽

Multidrug Transporters

SUMMARY One of the mechanisms that bacteria utilize to evade the toxic effects of antibiotics is the active extrusion of structurally unrelated drugs from the cell. Both intrinsic and acquired multidrug transporters play an important role in antibiotic resistance of several pathogens, including Neisseria gonorrhoeae, Mycobacterium tuberculosis, Staphylococcus aureus, Streptococcus pneumoniae, Pseudomonas aeruginosa, and Vibrio cholerae. Detailed knowledge of the molecular basis of drug recognition and transport by multidrug transport systems is required for the development of new antibiotics that are not extruded or of inhibitors which block the multidrug transporter and allow traditional antibiotics to be effective. This review gives an extensive overview of the currently known multidrug transporters in bacteria. Based on energetics and structural characteristics, the bacterial multidrug transporters can be classified into five distinct families. Functional reconstitution in liposomes of purified multidrug transport proteins from four families revealed that these proteins are capable of mediating the export of structurally unrelated drugs independent of accessory proteins or cytoplasmic components. On the basis of (i) mutations that affect the activity or the substrate specificity of multidrug transporters and (ii) the three-dimensional structure of the drug-binding domain of the regulatory protein BmrR, the substrate-binding site for cationic drugs is predicted to consist of a hydrophobic pocket with a buried negatively charged residue that interacts electrostatically with the positively charged substrate. The aromatic and hydrophobic amino acid residues which form the drug-binding pocket impose restrictions on the shape and size of the substrates. Kinetic analysis of drug transport by multidrug transporters provided evidence that these proteins may contain multiple substrate-binding sites.

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