Publications by authors named "Adepu K Kumar"

Metabolomics, the study of small-molecule metabolites within biological systems, has become a potent instrument for understanding cellular processes. Despite its profound insights into health, disease, and drug development, identifying the protein partners for metabolites, especially dietary phytochemicals, remains challenging. In the present study, we introduced an innovative in silico, structure-based target prediction approach to efficiently predict protein targets for metabolites.

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A canonical view of the primary physiological function of myoglobin (Mb) is that it is an oxygen (O) storage protein supporting mitochondrial oxidative phosphorylation, especially as the tissue O partial pressure (Po) drops and Mb off-loads O. Besides O storage/transport, recent findings support functions for Mb in lipid trafficking and sequestration, interacting with cellular glycolytic metabolites such as lactate (LAC) and pyruvate (PYR), and "ectopic" expression in some types of cancer cells and in brown adipose tissue (BAT). Data from Mb knockout (Mb) mice and biochemical models suggest additional metabolic roles for Mb, especially regulation of nitric oxide (NO) pools, modulation of BAT bioenergetics, thermogenesis, and lipid storage phenotypes.

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Myoglobin (Mb) interaction with the outer mitochondrial membrane (OMM) promotes oxygen (O) release. However, comprehensive molecular details on specific contact regions of the OMM with oxygenated (oxy-) and deoxygenated (deoxy-)Mb are missing. We used molecular dynamics (MD) simulations to explore the interaction of oxy- and deoxy-Mb with the membrane lipids of the OMM in two lipid compositions: (a) a typical whole membrane on average, and (b) specifically the cardiolipin-enriched cristae region (contact site).

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Previous research has indicated that various metabolites belonging to phenolic acids (PAs), produced by gut microflora through the breakdown of polyphenols, help in promoting bone development and protecting bone from degeneration. Results have also suggested that G-protein-coupled receptor 109A (GPR109A) functions as a receptor for those specific PAs such as hippuric acid (HA) and 3-(3-hydroxyphenyl) propionic acid (3-3-PPA). Indeed, HA has a molecular structural similarity with nicotinic acid (niacin) which has been shown previously to bind to GPR109A receptor and to mediate antilipolytic effects; however, the binding pocket and the structural nature of the interaction remain to be recognized.

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Myoglobin (Mb), besides its roles as an oxygen (O) carrier/storage protein and nitric oxide NO scavenger/producer, may participate in lipid trafficking and metabolite binding. Our recent findings have shown that O is released from oxy-Mb upon interaction with lactate (LAC, anerobic glycolysis end-product). Since pyruvate (PYR) is structurally similar and metabolically related to LAC, we investigated the effects of PYR (aerobic glycolysis end-product) on Mb using isothermal titration calorimetry, circular dichroism, and O-kinetic studies to evaluate PYR affinity toward Mb and to compare the effects of PYR and LAC on O release kinetics of oxy-Mb.

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Acifran is a well-known agonist of G-protein-coupled receptor protein, namely GPR109A. Acifran is primarily used in the treatment of dyslipidemia, myocardial infractions, and atherosclerosis in humans due to its lower vascular and metabolic side effects. However, experimental and computational studies on interaction sites of acifran with GPR proteins (GPR109A and GPR109B) are lacking.

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Myoglobin (Mb)-mediated oxygen (O) delivery and dissolved O in the cytosol are two major sources that support oxidative phosphorylation. During intense exercise, lactate (LAC) production is elevated in skeletal muscles as a consequence of insufficient intracellular O supply. The latter results in diminished mitochondrial oxidative metabolism and an increased reliance on nonoxidative pathways to generate ATP.

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The transmembrane G-protein coupled receptor GPR109A has been previously shown to function as a receptor for niacin in mediating antilipolytic effects. Although administration of high doses of niacin has shown beneficial effects on lipid metabolism, however, it is often accompanied by disturbing side effects such as flushing, liver damage, glucose intolerance, or gastrointestinal problems. Thus, it is important to understand niacin-GPR109A interactions, which can be beneficial for the development of alternate drugs having antilipolytic effects with less or no side effects.

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The current study demonstrates a comprehensive investigation on clean water generation from raw dairy wastewater (RDW) using a robust microalgal strain, Ascochloris sp. ADW007 and its growth, biomass, and lipid productivities in outdoor conditions. Microalgal treatment studies were conducted in column photobioreactor (CPB) and flat-pate photobioreactor (FPB), where the volumetric algal biomass productivity in RDW was significantly increased in both CPB (0.

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Disulfide reductases reduce other proteins and are critically important for cellular redox signaling and homeostasis. is a methane-producing microbe from the domain Archaea that produces a ferredoxin:disulfide reductase (FDR) for which the crystal structure has been reported, yet its biochemical mechanism and physiological substrates are unknown. FDR and the extensively characterized plant-type ferredoxin:thioredoxin reductase (FTR) belong to a distinct class of disulfide reductases that contain a unique active-site [4Fe-4S] cluster.

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β-Xylosidase plays an important role in xylan degradation by relieving the end product inhibition of endo-xylanase caused by xylo-oligosaccharides. β-Xylosidase has a wide range of applications in food, feed, paper and pulp, pharmaceutical industries and in bioconversion of lignocellulosic biomass. Hence, in the present study focused on purification, biochemical characterization and partial sequencing of purified β-xylosidase from xylanolytic strain Aspergillus niger ADH-11.

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Lignocellulosic feedstock materials are the most abundant renewable bioresource material available on earth. It is primarily composed of cellulose, hemicellulose, and lignin, which are strongly associated with each other. Pretreatment processes are mainly involved in effective separation of these complex interlinked fractions and increase the accessibility of each individual component, thereby becoming an essential step in a broad range of applications particularly for biomass valorization.

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Glutaredoxins (GRXs) are thiol-disulfide oxidoreductases abundant in prokaryotes, although little is understood of these enzymes from the domain Archaea. The numerous characterized GRXs from the domain Bacteria utilize a diversity of low-molecular-weight thiols in addition to glutathione as reductants. We report here the biochemical and structural properties of a GRX-like protein named methanoredoxin (MRX) from Methanosarcina acetivorans of the domain Archaea.

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The present investigation demonstrated pretreatment of lignocellulosic biomass rice straw using natural deep eutectic solvents (NADESs), and separation of high-quality lignin and holocellulose in a single step. Qualitative analysis of the NADES extract showed that the extracted lignin was of high purity (>90 %), and quantitative analysis showed that nearly 60 ± 5 % (w/w) of total lignin was separated from the lignocellulosic biomass. Addition of 5.

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Bioinformatics analyses predict the distribution in nature of several classes of diverse disulfide reductases that evolved from an ancestral plant-type ferredoxin:thioredoxin reductase (FTR) catalytic subunit to meet a variety of ecological needs. Methanosarcina acetivorans is a methane-producing species from the domain Archaea predicted to encode an FTR-like enzyme with two domains, one resembling the FTR catalytic subunit and the other containing a rubredoxin-like domain replacing the variable subunit of present-day FTR enzymes. M.

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The genome of Methanosarcina acetivorans contains a gene (ma1659) that is predicted to encode an uncharacterized chimeric protein containing a plant-type ferredoxin/thioredoxin reductase-like catalytic domain in the N-terminal region and a bacterial-like rubredoxin domain in the C-terminal region. To understand the structural and functional properties of the protein, the ma1659 gene was cloned and overexpressed in Escherichia coli. Crystals of the MA1659 protein were grown by the sitting-drop method using 2 M ammonium sulfate, 0.

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An Aspergillus terreus, isolated from oil contaminated soil, could degrade a wide range of petroleum hydrocarbons including the immediate oxidation products of hydrocarbons, like alkanols and alkanals. Among all the linear chain carbon substrates, highest growth of 39.1 + or - 3.

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A multimeric alcohol oxidase from Aspergillus terreus was dissociated and simultaneously deflavinated into catalytically inactive FAD-free subunits when incubated with 0.74 M beta-mercaptoethanol (beta-ME) for 8 h at 4 degrees C. This dissociation process had traversed through two FAD-associated intermediate proteins, between these one of them showed the enzyme activity.

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An alcohol oxidase was isolated from the microsome of n-hexadecane grown Aspergillus terreus and purified by ion exchange chromatography. The oxidase was found to act on short chain-, long chain-, secondary-, and aromatic-alcohol substrates with highest affinity for n-heptanol (K(M)=0.498 mM, K(cat)=2.

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