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De novo metalloprotein design is a remarkable approach to shape protein scaffolds toward specific functions. Here, we report the design and characterization of Due Rame 1 (DR1), a de novo designed protein housing a di-copper site and mimicking the Type 3 (T3) copper-containing polyphenol oxidases (PPOs). To achieve this goal, we hierarchically designed the first and the second di-metal coordination spheres to engineer the di-copper site into a simple four-helix bundle scaffold. Spectroscopic, thermodynamic, and functional characterization revealed that DR1 recapitulates the T3 copper site, supporting different copper redox states, and being active in the O -dependent oxidation of catechols to o-quinones. Careful design of the residues lining the substrate access site endows DR1 with substrate recognition, as revealed by Hammet analysis and computational studies on substituted catechols. This study represents a premier example in the construction of a functional T3 copper site into a designed four-helix bundle protein.
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http://dx.doi.org/10.1002/anie.202211552 | DOI Listing |
ACS Omega
September 2025
Mads Clausen Institute, NanoSYD, University of Southern Denmark (SDU), Alsion 2, 6400 Sønderborg, Denmark.
Detection of micro- and nanoplastic particles at extremely low concentrations in complex matrices is a critical goal in environmental science and regulatory frameworks. Surface-enhanced Raman spectroscopy (SERS) offers unique advantages for detecting molecular species in such mixtures, relying solely on their characteristic fingerprints. However, its application for plastic particles has been constrained due to weak analyte-substrate interactions.
View Article and Find Full Text PDFBMB Rep
September 2025
Department of Microbiology and Immunology, Yonsei University College of Medicine, Seoul, 03722, Republic of Korea; Brain Korea 21 PLUS Project for Medical Sciences, Yonsei University College of Medicine, Seoul, 03722, Republic of Korea; Institute for Immunology and Immunological Diseases, Yonsei Uni
B cell tolerance is critical for preventing autoimmunity, yet the mechanisms by which B cells discriminate self from non-self antigens remain incompletely understood. While early findings emphasize the role of classical antigen-mediated BCR signaling strength by varying antigen formats, emerging evidence highlights the importance of mechanical cues during antigen recognition. This review explores how mechanosensitive ion channels, particularly Piezo1, contribute to B cell activation and tolerance by integrating physical forces at the immune synapse.
View Article and Find Full Text PDFBiosens Bioelectron
August 2025
State Key Laboratory of Frigid Zone Cardiovascular Diseases (SKLFZCD), College of Pharmacy, Harbin Medical University, Heilongjiang, 150081, China; Research Unit of Health Sciences and Technology (HST), Faculty of Medicine University of Oulu, Finland; Heilongjiang Eye Hospital, Harbin, 150001, China
SERS has revolutionized viral detection with its high sensitivity and specificity. This review comprehensively explores the application progress, challenges, and future directions of SERS in viral detection. Firstly, the fundamental principles of SERS are introduced.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
September 2025
State Key Laboratory of Chemo and Biosensing, School of Biomedical Sciences, Hunan University, Changsha, 410082, China.
Activity-based ubiquitin probes (Ub-ABPs) are powerful tools for studying the functional landscape of deubiquitinases (DUBs). While most existing Ub probes have focused on examining the native state of DUBs, oxidative stress, especially in cancer and inflammatory contexts, can oxidize the catalytic cysteine of DUBs, significantly altering their activity. Here, we developed three novel ubiquitin-based activity probes (Ub-ABPs) to selectively trap the sulfenylated form of deubiquitinases (DUB-SOH).
View Article and Find Full Text PDFJ Biol Chem
September 2025
Department of Chemistry and Center for Molecular Signaling, Wake Forest University, Winston-Salem, NC, 27109. Electronic address:
The AUA isoleucine codon is generally rare and used with varying frequency in bacterial genomes. The tRNA responsible for decoding this trinucleotide must be modified at the wobble position by tRNA lysidine synthetase (TilS) prior to aminoacylation and accommodation at the ribosome. To test the hypothesis that TilS catalytic efficiency correlates with AUA frequency, we cloned tilS genes from bacteria with varying AUA codon usage.
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