A recombinant dengue 2 virus NS2B-NS3 protease (NS means non-structural virus protein) was compared with human furin for the capacity to process short peptide substrates corresponding to seven native substrate cleavage sites in the dengue viral polyprotein. Using fluorescence resonance energy transfer peptides to measure kinetics, the processing of these substrates was found to be selective for the Dengue protease. Substrates containing two or three basic amino acids (Arg or Lys) in tandem were found to be the best, with Abz-AKRRSQ-EDDnp being the most efficiently cleaved. The hydrolysis of dipeptide substrates Bz-X-Arg-MCA where X is a non-natural basic amino acid were also kinetically examined, the best substrates containing aliphatic basic amino acids. Our results indicated that proteolytic processing by dengue NS3 protease, tethered to its activating NS2B co-factor, was strongly inhibited by Ca2+ and kosmotropic salts of the Hofmeister's series, and significantly influenced by substrate modifications between S4 and S6'. Incorporation of basic non-natural amino acids in short peptide substrates had significant but differential effects on Km and k(cat), suggesting that further dissection of their influences on substrate affinity might enable the development of effective dengue protease inhibitors.
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http://dx.doi.org/10.1016/j.abb.2006.11.005 | DOI Listing |
EMBO J
January 2025
Department of Geriatrics, Gerontology Institute of Anhui Province, Centre for Leading Medicine and Advanced Technologies of IHM, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China.
mTOR plays a pivotal role in cancer growth control upon amino acid response. Recently, CDK inhibitor P27KIP1 has been reported as a noncanonical inhibitor of mTOR signaling in MEFs, via unclear mechanisms. Here, we find that P27KIP1 degradation via E3 ligase TRIM21 is inhibited by human micropeptide hSPAR through its C-terminus (hSPAR-C), causing P27KIP1's cytoplasmic accumulation in breast cancer cells.
View Article and Find Full Text PDFFood Chem
January 2025
College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China. Electronic address:
This study aimed to investigate the inhibitory pathways of basic amino acids (Histidine, Lysine, and Arginine) on the formation of PhIP in the glucose/creatinine/phenylalanine model system. The inhibitory effects were found to depend on both the chemical structure and concentration of the basic amino acids, with Lysine showing the strongest inhibitory effect. Due to the lower reaction barrier of basic amino acids, their potential inhibitory mechanism is proposed to involve competition with phenylalanine for glucose.
View Article and Find Full Text PDFMicrobiol Spectr
January 2025
Office of Vaccine Research and Review, Center for Biologics Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, USA.
Although much has been learned about the entry mechanism of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), many details of the entry mechanisms of seasonal human coronaviruses (HCoVs) remain less well understood. In the present study, we used 293T cell lines stably expressing angiotensin converting enzyme (ACE2), aminopeptidase N (APN), or transmembrane serine protease 2 (TMPRSS2), which support high-level transduction of lentiviral pseudoviruses bearing spike proteins of seasonal HCoVs, HCoV-NL63, -229E, or -HKU1, respectively, to compare spike processing and virus entry pathways among these viruses. Our results showed that the entry of HCoV-NL63, -229E, and -HKU1 pseudoviruses into cells is sensitive to endosomal acidification inhibitors (chloroquine and NHCl), indicating entry via the endocytosis route.
View Article and Find Full Text PDFIET Syst Biol
January 2025
School of Computer Science and Technology, Baotou Medical College, Baotou, China.
Metal ions are significant ligands that bind to proteins and play crucial roles in cell metabolism, material transport, and signal transduction. Predicting the protein-metal ion ligand binding residues (PMILBRs) accurately is a challenging task in theoretical calculations. In this study, the authors employed fused amino acids and their derived information as feature parameters to predict PMILBRs using three classical machine learning algorithms, yielding favourable prediction results.
View Article and Find Full Text PDFJ Mater Chem B
January 2025
Department of Neurology, the First Affiliated Hospital of Anhui Medical University, Hefei 230022, Anhui, P. R. China.
Drug delivery for epilepsy treatment faces enormous challenges, where the sole focus on enhancing the ability of drugs to penetrate the blood-brain barrier (BBB) through ligand modification is insufficient because of the absence of seizure-specific drug accumulation. In this study, an amphipathic drug carrier with a glucose transporter (GLUT)-targeting capability was synthesised by conjugating 2-deoxy-2-amino-D-glucose (2-DG) to the model carrier DSPE-PEG. A 2-DG-modified nano drug delivery system (NDDS) possessing robust stability and favourable biocompatibility was then fabricated using the nanoprecipitation method.
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