Sortase-mediated protein ligation is a biological covalent conjugation system developed from the enzymatic cell wall display mechanism found in Staphylococcus aureus. This three-component system requires: (i) purified Sortase A (SrtA) enzyme; (ii) a substrate containing the LPXTG peptide recognition sequence; and (iii) an oligo-glycine acceptor molecule. We describe cloning of the single-chain antibody sc528, which binds to the extracellular domain of the epidermal growth factor receptor (EGFR), from the parental monoclonal antibody and incorporation of a LPETGG tag sequence. Utilizing recombinant SrtA, we demonstrate successful incorporation of biotin from GGG-biotin onto sc528. EGFR is an important cancer target and is over-expressed in human tumor tissues and cancer lines, such as the A431 epithelial carcinoma cells. SrtA-biotinylated sc528 specifically bound EGFR expressed on A431 cells, but not negative control lines. Similarly, when sc528 was labeled with fluorescein we observed antigen-specific labeling. The ability to introduce functionality into recombinant antibodies in a controlled, site-specific manner has applications in experimental, diagnostic, and potentially clinical settings. For example, we demonstrate addition of all three reaction components in situ within a biosensor flow cell, resulting in oriented covalent capture and presentation of sc528, and determination of precise affinities for the antibody-receptor interaction.
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http://dx.doi.org/10.1002/bit.24407 | DOI Listing |
Proc Natl Acad Sci U S A
January 2025
Department of Bioengineering, California Institute of Technology, Pasadena, CA 91125.
The diversity and heterogeneity of biomarkers has made the development of general methods for single-step quantification of analytes difficult. For individual biomarkers, electrochemical methods that detect a conformational change in an affinity binder upon analyte binding have shown promise. However, because the conformational change must operate within a nanometer-scale working distance, an entirely new sensor, with a unique conformational change, must be developed for each analyte.
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January 2025
Institute of Medical Microbiology, Rheinisch-Westfälische Technische Hochschule Aachen University Hospital, Aachen 52074, Germany.
Postnatal establishment of enteric metabolic, host-microbial and immune homeostasis is the result of precisely timed and tightly regulated developmental and adaptive processes. Here, we show that infection with the invasive enteropathogen Typhimurium results in accelerated maturation of the neonatal epithelium with premature appearance of antimicrobial, metabolic, developmental, and regenerative features of the adult tissue. Using conditional Myd88-deficient mice, we identify the critical contribution of immune cell-derived mediators.
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January 2025
Department of Cell & Developmental Biology, School of Biological Sciences, University of California San Diego, La Jolla, CA 92093.
A spectacular diversity of forms and features allow species to thrive in different environments, yet some structures remain relatively unchanged. Insect compound eyes are easily recognizable despite dramatic differences in visual abilities across species. It is unknown whether distant insect species use similar or different mechanisms to pattern their eyes or what types of genetic changes produce diversity of form and function.
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January 2025
Laboratory of Precision Medicine and Biopharmaceuticals, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China.
Recurrent missense mutations in the human epidermal growth factor receptor 2 (HER2) have been identified across various human cancers. Among these mutations, the active S310F mutation in the HER2 extracellular domain stands out as not only oncogenic but also confers resistance to pertuzumab, an antibody drug widely used in clinical cancer therapy, by impeding its binding. In this study, we have successfully employed computational-aided rational design to undertake directed evolution of pertuzumab, resulting in the creation of an evolved pertuzumab variant named Ptz-SA.
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January 2025
Ministry of Education Key Laboratory of Environment Remediation and Ecological Health, Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China.
While iron (Fe) is essential for life and plays important roles for almost all growth related processes, it can trigger cell death in both animals and plants. However, the underlying mechanisms for Fe-induced cell death in plants remain largely unknown. S-nitrosoglutathione reductase (GSNOR) has previously been reported to regulate nitric oxide homeostasis to prevent Fe-induced cell death within root meristems.
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