Curcumin Chalcone Derivatives Database (CCDD): a Python framework for natural compound derivatives database.

We built the Curcumin Chalcone Derivatives Database (CCDD) to enable the effective virtual screening of highly potent curcumin and its analogs. The two-dimensional (2D) structures were drawn using the ChemBioOffice package and converted to 3D structures using Discovery Studio Visualizer V 2021 (DS). The database was built using different Python modules. For the 3D structures, different Python packages were used to obtain the data frame of compounds. This framework is also used to visualize the compounds. The webserver enables the users to screen the compounds according to Lipinski's rule of five. The structures can be downloaded in .sdf and .mol format. The data frame (df) can be downloaded in .csv format. Our webserver can help computational drug discovery researchers find new therapeutics and build new webservers. The CCDD is freely available at: https://srampogu-ccdd-ccdd-8uldk8.streamlit.app/.

A New Perspective on Metabolites and Bioactive Compounds from Fungi.

Fungi play an important role in the solution to important global problems. Making use of processes and goods that are based on fungi can help promote sustainability by making the most efficient use of natural resources. Fungi stand apart from other organisms due to their extraordinary capacity to generate organic compounds. They are necessary for the psychological and physiological well-being of people worldwide. They are excellent producers of vitamins, pigments, hydrolytic enzymes, biofuels, organic acids, polysaccharides, and secondary metabolites such as antibiotics, anticancer treatments, hypocholesterolemic pharmaceuticals, and immunosuppressants. Other secondary metabolites include biofuels. In addition, polysaccharides are produced by them. We provide a condensed explanation of the significance of secondary metabolites in a variety of industries, such as the pharmaceutical industry, the food industry, the textile industry, and the transportation industry. In addition to providing a better understanding of biosynthetic regulation and the possibilities of genetic engineering, improved laboratory processes for the selection of nontoxigenic fungal strains have permitted the manufacture of larger quantities of safe commercial items. The significance of fungi in industrial settings is the topic that will be investigated in this review.

Kinetic evidence in favor of glyoxalase III and against deglycase activity of DJ-1.

DJ-1, a protein encoded by PARK7 plays a protective role against neurodegeneration. Since its glyoxalase III activity catalyzing methylglyoxal (MG) to lactate was discovered, DJ-1 has been re-established as a deglycase decomposing the MG-intermediates with amino acids and nucleotides (hemithioacetal and hemiaminal) rather than MG itself, but it is still debatable. Here, we have clarified that human DJ-1 directly recognizes MG, and not MG-intermediates, by monitoring the detailed catalytic processes and enantiomeric lactate products. The hemithioacetal intermediate between C106 of 15 N-labeled DJ-1 (15N DJ-1) and MG was also monitored by NMR. TRIS molecule formed stable diastereotopic complexes with MG (Kd , 1.57 ± 0.27 mM) by utilizing its three OH groups, which likely disturbed the assay of deglycase activity. The low kcat of DJ-1 for MG and its MG-induced structural perturbation may suggest that DJ-1 has a regulatory function as an in vivo sensor of reactive carbonyl stress.

NMR Titration Studies in Z-DNA Dynamics.

Chemical shift perturbation (CSP) is a simple NMR technique for studying the DNA binding of proteins. Titration of the unlabeled DNA into the 15N-labeled protein is monitored by acquiring a two-dimensional (2D) heteronuclear single-quantum correlation (HSQC) spectrum at each step of the titration. CSP can also provide information on the DNA-binding dynamics of proteins, as well as protein-induced conformational changes in DNA. Here, we describe the titration of DNA for the 15N-labeled Z-DNA-binding protein, monitored via 2D HSQC spectra. NMR titration data can be analyzed with the active B-Z transition model to provide the protein-induced B-Z transition dynamics of DNA.

Amino-Acid-Substituted Perylene Diimide as the Organic Cathode Materials for Lithium-Ion Batteries.

One of the most effective cost reduction and green engineering projects is to introduce organic compounds to electrode materials instead of expensive inorganic-based materials. In this work, derivatives of perylene diimide substituted with amino acids (PDI_AAs) showed the characteristics of redox-active organic compounds and were, therefore, used as cathode materials of lithium-ion batteries (LIBs). Among the as-synthesized PDI_AAs, the L-alanine-substituted PDI (PDI_A) showed the most improved cycling performances of 86 mAhg-1 over 150 cycles with retention of 95% at 50 mAg-1. Furthermore, at a high current density of 500 mAg-1, PDI_A exhibited a long-term cycling performance of 47 mAhg-1 (retention to 98%) over 5000 cycles. In addition, ex situ attenuated total reflection Fourier-transform infrared spectroscopy (ATR FT-IR) analysis of electrodes at various charging states showed the mechanism of the charge-discharge process of PDI_A.

New Understandings from the Biophysical Study of the Structure, Dynamics, and Function of Nucleic Acids 2.0.

Nucleic acids play an essential role in all biological processes related to genetic information, such as replication, transcription, translation, repair, and recombination [...].

Phytotherapeutic applications of alkaloids in treating breast cancer.

Breast cancer is one of the major causes of mortality in women worldwide. The current treatments available are radiation therapy (RT), surgery, endocrine (hormone) therapy (ET), chemotherapy (CT), and targeted therapy. These treatments are associated with certain side effects that demand the use of natural compounds due to their lower to negligible side effects. One such category of natural compounds is alkaloids. Alkaloids are a group of natural compounds that have gained widespread attention due to their use as potential therapeutics. Alkaloids exert anti-inflammatory and antiviral properties along with antimicrobial activities. In the current review, 12 alkaloids are reviewed in detail for their potential in treating breast cancer. These alkaloids have been shown to induce apoptosis, decrease tumor volume, inhibit cell proliferation and migration, and induce autophagy and they can also be used as a component of combination therapy. This review provides comprehensive information on the in vitro and in vivo therapeutic abilities of alkaloids to counteract breast cancer.

A Green Chemical Approach for Iodination of Pyrimidine Derivatives by Mechanical Grinding under Solvent-Free Conditions.

The iodination of pyrimidines is usually carried out by using toxic reagents under acidic conditions, such as with sulfuric acid and nitric acid. To avoid toxic reagents, we developed a simple and eco-friendly approach for the iodination of pyrimidine derivatives under solvent-free conditions using solid iodine and AgNO3 as an electrophilic iodinating reagent. The advantages of this method are the relatively short reaction time (20-30 min), simple set-up procedure, high yields (70-98%), and environmentally friendly reaction conditions. Our novel approach for the iodination of pyrimidines, as well as a variety of their derivatives, will contribute to the development of nucleobase-related drug candidates.

Salt Dependence of DNA Binding Activity of Human Transcription Factor Dlx3.

Distal-less 3 (Dlx3) is a homeobox-containing transcription factor and plays a crucial role in the development and differentiation process. Human Dlx3 consists of two transactivation domains and a homeobox domain (HD) that selectively binds to the consensus site (5'-TAATT-3') of the DNA duplex. Here, we performed chemical shift perturbation experiments on Dlx3-HD in a complex with a 10-base-paired (10-bp) DNA duplex under various salt conditions. We also acquired the imino proton spectra of the 10-bp DNA to monitor the changes in base-pair stabilities during titration with Dlx3-HD. Our study demonstrates that Dlx3-HD selectively recognizes its consensus DNA sequences through the α3 helix and L1 loop regions with a unique dynamic feature. The dynamic properties of the binding of Dlx3-HD to its consensus DNA sequence can be modulated by varying the salt concentrations. Our study suggested that this unique structural and dynamic feature of Dlx3-HD plays an important role in target DNA recognition, which might be associated with tricho-dento-osseous syndrome.

Biophysical Study of the Structure, Dynamics, and Function of Nucleic Acids.

Nucleic acids have essential roles in all biological processes related to genetic information, such as replication, transcription, translation, repair, and recombination [...].

Separation of native and C106-oxidized DJ-1 proteins by using column chromatography.

Mutations in PARK7, the gene encoding the DJ-1 protein, are associated with early onset of Parkinson's disease. The C106 residue of DJ-1 is highly susceptible to oxidation, and its oxidation status is essential for various in vivo neuroprotective roles. Since C106 is readily oxidized to sulfinic acid that is not reduced by dithiothreitol, no method to separate native DJ-1 protein from the oxidized one creates challenges in the in vitro study of the biological relevance of C106-oxidation state. Here, we report an efficient column chromatography method to purify native, C106-sulfinic, and mixed (combination of the priors) forms of DJ-1. This method will be useful for systematic in vitro studies of DJ-1 functions by providing specific native and C106-sulfinic DJ-1 proteins.

Conformational exchange of the Zα domain of human RNA editing enzyme ADAR1 studied by NMR spectroscopy.

Z-DNA binding proteins (ZBPs) play important roles in RNA editing, innate immune responses, and viral infections. Numerous studies have implicated a role for conformational motions during ZBPs binding upon DNA, but the quantitative intrinsic conformational exchanges of ZBP have not been elucidated. To understand the correlation between the biological function and dynamic feature of the Zα domains of human ADAR1 (hZαADAR1), we have performed the 15N backbone amide Carr-Purcell-Meiboom-Gill (CPMG) relaxation dispersion experiments on the free hZαADAR1 at two different magnetic fields at 35 °C. The robust inter-dependence of parameters in the global fitting process using multi-magnetic field CPMG profiles allows us characterizing the dynamic properties of conformational changes in hZαADAR1. This study found that free hZαADAR1 exhibited the conformational exchange with a kex of 5784 s-1 between the states "A" (89% population) and "B" (11% population). The different hydrophobic interactions among helices α1, α2, and α3 between these two states might correlate with efficient Z-DNA binding achieved by the hydrogen bonding interactions between its side-chains and the phosphate backbone of Z-DNA.

Non-Canonical Helical Structure of Nucleic Acids Containing Base-Modified Nucleotides.

Chemically modified nucleobases are thought to be important for therapeutic purposes as well as diagnosing genetic diseases and have been widely involved in research fields such as molecular biology and biochemical studies. Many artificially modified nucleobases, such as methyl, halogen, and aryl modifications of purines at the C8 position and pyrimidines at the C5 position, are widely studied for their biological functions. DNA containing these modified nucleobases can form non-canonical helical structures such as Z-DNA, G-quadruplex, i-motif, and triplex. This review summarizes the synthesis of chemically modified nucleotides: (i) methylation, bromination, and arylation of purine at the C8 position and (ii) methylation, bromination, and arylation of pyrimidine at the C5 position. Additionally, we introduce the non-canonical structures of nucleic acids containing these modifications.

Base-Pair Opening Dynamics Study of Fluoride Riboswitch in the Bacillus cereus CrcB Gene.

Riboswitches are segments of noncoding RNA that bind with metabolites, resulting in a change in gene expression. To understand the molecular mechanism of gene regulation in a fluoride riboswitch, a base-pair opening dynamics study was performed with and without ligands using the Bacillus cereus fluoride riboswitch. We demonstrate that the structural stability of the fluoride riboswitch is caused by two steps depending on ligands. Upon binding of a magnesium ion, significant changes in a conformation of the riboswitch occur, resulting in the greatest increase in their stability and changes in dynamics by a fluoride ion. Examining hydrogen exchange dynamics through NMR spectroscopy, we reveal that the stabilization of the U45·A37 base-pair due to the binding of the fluoride ion, by changing the dynamics while maintaining the structure, results in transcription regulation. Our results demonstrate that the opening dynamics and stabilities of a fluoride riboswitch in different ion states are essential for the genetic switching mechanism.

Systematic Approach to Find the Global Minimum of Relaxation Dispersion Data for Protein-Induced B-Z Transition of DNA.

Carr-Purcell-Meiboom-Gill (CPMG) relaxation dispersion spectroscopy is commonly used for quantifying conformational changes of protein in µs-to-ms timescale transitions. To elucidate the dynamics and mechanism of protein binding, parameters implementing CPMG relaxation dispersion results must be appropriately determined. Building an analytical model for multi-state transitions is particularly complex. In this study, we developed a new global search algorithm that incorporates a random search approach combined with a field-dependent global parameterization method. The robust inter-dependence of the parameters carrying out the global search for individual residues (GSIR) or the global search for total residues (GSTR) provides information on the global minimum of the conformational transition process of the Zα domain of human ADAR1 (hZαADAR1)-DNA complex. The global search results indicated that a α-helical segment of hZαADAR1 provided the main contribution to the three-state conformational changes of a hZαADAR1-DNA complex with a slow B-Z exchange process. The two global exchange rate constants, kex and kZB, were found to be 844 and 9.8 s-1, respectively, in agreement with two regimes of residue-dependent chemical shift differences-the "dominant oscillatory regime" and "semi-oscillatory regime". We anticipate that our global search approach will lead to the development of quantification methods for conformational changes not only in Z-DNA binding protein (ZBP) binding interactions but also in various protein binding processes.

Molecular basis of ice-binding and cryopreservation activities of type III antifreeze proteins.

Antifreeze proteins (AFPs) can inhibit the freezing of body fluid at subzero temperatures to promote the survival of various organisms living in polar regions. Type III AFPs are categorized into three subgroups, QAE1, QAE2, and SP isoforms, based on differences in their isoelectric points. We determined the thermal hysteresis (TH), ice recrystallization inhibition (IRI), and cryopreservation activity of three isoforms of the notched-fin eelpout AFP and their mutant constructs and characterized their structural and dynamic features using NMR. The QAE1 isoform is the most active among the three classes of III AFP isoforms, and the mutants of inactive QAE2 and SP isoforms, QAE2ACT and SPACT, displayed the full TH and IRI activities with resepect to QAE1 isoform. Cryopreservation studies using mouse ovarian tissue revealed that the QAE1 isoform and the active mutants, QAE2ACT and SPACT, more effectively preserved intact follicle morphology and prevented DNA double-strand break damage more efficiently than the inactive isoforms. It was also found that all active AFPs, QAE1, QAE2ACT, and SPACT, formed unique H-bonds with the first 310 helix, an interaction that plays an important role in the formation of anchored clathrate water networks for efficient binding to the primary prism and pyramidal planes of ice crystals, which was disrupted in the inactive isoforms. Our studies provide valuable insights into the molecular mechanism of the TH and IRI activity, as well as the cryopreservation efficiency, of type III AFPs.

Protein-induced B-Z transition of DNA duplex containing a 2'-OMe guanosine.

Structural transformation of the canonical right-handed helix, B-DNA, to the non-canonical left-handed helix, Z-DNA, can be induced by the Zα domain of the human RNA editing enzyme ADAR1 (hZαADAR1). To characterize the site-specific preferences of binding and structural changes in DNA containing the 2'-O-methyl guanosine derivative (mG), titration of the imino proton spectra and chemical shift perturbations were performed on hZαADAR1 upon binding to Z-DNA. The structural transition between B-Z conformation as the changing ratio between DNA and protein showed a binding affinity of the modified DNA onto the Z-DNA binding protein similar to wild-type DNA or RNA. The chemical shift perturbation results showed that the overall structure and environment of the modified DNA revealed DNA-like properties rather than RNA-like characteristics. Moreover, we found evidence for two distinct regimes, "Z-DNA Sensing" and "Modification Sensing", based on the site-specific chemical shift perturbation between the DNA (or RNA) binding complex and the modified DNA-hZαADAR1 complex. Thus, we propose that modification of the sugar backbone of DNA with 2'-O-methyl guanosine promotes the changes in the surrounding α3 helical structural segment as well as the non-perturbed feature of the ß-hairpin region.

C-Jun N-terminal kinase inhibitors: Structural insight into kinase-inhibitor complexes.

The activation of c-Jun N-terminal kinases (JNKs) plays an important role in physiological processes including neuronal function, immune activity, and development, and thus, JNKs have been a therapeutic target for various diseases such as neurodegenerative diseases, inflammation, and cancer. Efforts to develop JNK-specific inhibitors have been ongoing for several decades. In this process, the structures of JNK in complex with various inhibitors have contributed greatly to the design of novel compounds and to the elucidation of structure-activity relationships. Almost 100 JNK structures with various compounds have been determined. Here we summarize the information gained from these structures and classify the inhibitors into several groups based on the binding mode. These groups include inhibitors in the open conformation and closed conformation of the gatekeeper residue, non-ATP site binders, peptides, covalent inhibitors, and type II kinase inhibitors. Through this work, deep insight into the interaction of inhibitors with JNKs can be gained and this will be helpful for developing novel, potent, and selective inhibitors.

NMR mapping of the highly flexible regions of 13C/15N-labeled antibody TTAC-0001-Fab.

Monoclonal antibody (mAb) drugs are clinically important for the treatment of various diseases. TTAC-0001 is under development as a new anti-cancer antibody drug targeting VEGFR-2. As the less severe toxicity of TTAC-0001 compared to Bevacizumab, likely due to the decreased in vivo half-life, seems to be related to its structural flexibility, it is important to map the exact flexible regions. Although the 13C/15N-labeled protein is required for NMR analyses, it is difficult to obtain antibody fragments (Fab and scFv) containing disulfide bonds through general cytosolic expression in Escherichia coli (E. coli). Here, we notably increased the periplasmic expression of the 13C/15N-labeled TTAC-0001-Fab (13C/15N-TTAC-Fab) through simple isopropyl ß-D-1-thiogalactopyranoside (IPTG)-induction at an increased optical density (1.5 OD600nm). Through NMR triple resonance experiments, two loop insertions (LI-1 between the VH and CH1; LI-2 between the VL and CL) were confirmed to be highly flexible. The additional LIs could be another way to engineer the antibody by changing the pharmacokinetic properties.

Dynamics Studies of DNA with Non-canonical Structure Using NMR Spectroscopy.

The non-canonical structures of nucleic acids are essential for their diverse functions during various biological processes. These non-canonical structures can undergo conformational exchange among multiple structural states. Data on their dynamics can illustrate conformational transitions that play important roles in folding, stability, and biological function. Here, we discuss several examples of the non-canonical structures of DNA focusing on their dynamic characterization by NMR spectroscopy: (1) G-quadruplex structures and their complexes with target proteins; (2) i-motif structures and their complexes with proteins; (3) triplex structures; (4) left-handed Z-DNAs and their complexes with various Z-DNA binding proteins. This review provides insight into how the dynamic features of non-canonical DNA structures contribute to essential biological processes.