Betalains, a group of pigments widely distributed in various plants, are extensively applied in the food, beverage, and medicinal industries. The biosynthesis of betalains involves the enzymatic action of 4,5-DOPA-dioxygenase, which catalyzes the key ring-opening reaction of DOPA to produce betalamic acid, a crucial intermediate in the pathway. The crystal structure of a 4,5-DOPA-dioxygenase from (BvDOD) was determined in this study. The structural analysis revealed that BvDOD exhibited a structural fold similar to that of other members of the extradiol dioxygenase family. Moreover, the Fe-ligand residues His15, His53, and His229 indicated the enzyme's reliance on nonheme iron for catalyzing the ring-opening reaction. Molecular docking and mutational analysis identified two conserved residues, His119 and His175, in the active site essential for the catalytic reaction. In addition, Thr17, Asp254, and Tyr260 contributed to properly positioning the substrate in the active site. This study has provided structural insights into substrate recognition and catalytic mechanisms of BvDOD, which can be applied to develop enzymes for improved betalain production.
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http://dx.doi.org/10.1021/acs.jafc.4c09501 | DOI Listing |
J Am Chem Soc
March 2025
Institute of Biological Chemistry, Academia Sinica, No. 128, Sec. 2, Academia Road, Nankang, Taipei 115, Taiwan.
In this study, the role of phosphorylation in the liquid-liquid phase separation (LLPS) of tau, the underlying driving forces, and the potential implications of this separation on protein conformation and subsequent protein aggregation were investigated. We compared in vivo-produced phosphorylated tau (p-tau) and nonphosphorylated tau under different coacervation conditions without adding crowding agents. Our findings revealed that spontaneous phase separation occurs exclusively in p-tau, triggered by a temperature shift from 4 °C to room temperature, and is driven by electrostatic and hydrophobic interactions.
View Article and Find Full Text PDFACS Nano
March 2025
School of Chemical Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China.
The self-assemblies of topological complex block copolymers, especially the AB type miktoarm star ones, are fascinating topics in the soft matter field, which represent typical self-assembly behaviors analogous to those of biological membranes. However, their diverse topological asymmetries and versatile spontaneous curvatures result in rather complex phase separations that deviate significantly from the common mechanisms. Thus, numerous trial-and-error experiments with tremendous parameter space and intricate relationships are needed to study their assemblies.
View Article and Find Full Text PDFAnal Chim Acta
May 2025
State Key Laboratory of Natural Medicines, China Pharmaceutical University, No. 639 Longmian Dadao, Nanjing, 211198, China. Electronic address:
Background: Traditional studies of protein responses to external stimuli primarily focus on changes in protein abundance, often overlooking the critical role of protein conformational alterations. To address this gap, we developed Protein Abundance and Conformation Analysis (PACA), an integrative method that quantifies both protein abundance and conformational changes. PACA combines conventional quantitative proteomics for abundance measurements with Target Response Accessibility Profiling (TRAP), a technique that captures conformational changes in situ by applying reductive dimethylation to label accessible lysine residues in living cells before lysis.
View Article and Find Full Text PDFJ Genet Eng Biotechnol
March 2025
Department of Veterinary Parasitology, College of Veterinary Science, Lala Lajpat Rai University of Veterinary and Animal Sciences, Hisar, Haryana 125004, India.
The hard tick Hyalomma dromedarii, a vector for numerous animal and human pathogens, was investigated for genetic diversity using the mitochondrial cytochrome C oxidase subunit I (cox I) and 16S ribosomal RNA (16S rRNA) genes. Hyalomma dromedarii sequences (n = 11 cox I; n = 7 16S rRNA) were deposited in GenBank (LC761179-89, LC761173-78, LC654692), showing 99.52-100 % (cox I) and 98.
View Article and Find Full Text PDFJ Genet Eng Biotechnol
March 2025
Department of Bioinformatics, University of North Bengal, District-Darjeeling, West Bengal 734013, India. Electronic address:
Background: Acquired Immunodeficiency Syndrome (AIDS) is a critical global health issue caused by the human immunodeficiency virus (HIV). It has different strains and subtypes; among these, Subtype C accounts for higher infection rates than others. Despite its high prevalence, the molecular interactions with host receptors, specifically CD4, have not yet been explored.
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