In general, proteins in the biological system interact with nanoparticles (NPs) via adsorption on the particle surface. Understanding the adsorption at the molecular level is crucial to explore NP-protein interactions. The increasing concerns about the risk to human health on NP exposure have been explored through the discovery of a handful protein biomarkers and biochemical analysis. However, detailed information on structural perturbation and associated functional changes of proteins on interaction with NPs is limited. Erythrocytes (red blood cells) are devoid of defense mechanism of protecting NP penetration through endocytosis. Therefore, it is important to investigate the interaction of erythrocyte proteins with NPs. Hemoglobin, the most abundant protein of human erythrocyte, is a tetrameric molecule consisting of α- and β-globin chains in duplicate. In the present study, we have used hemoglobin as a model system to investigate NP-protein interaction with ferric pyrophosphate NPs [NP-Fe(PO)]. We report the formation of a bioconjugate of hemoglobin upon adsorption to NP-Fe(PO) surface. Analysis of the bioconjugate indicated that Fe ion of NP-Fe(PO) contributed in the bioconjugate formation. Using hydrogen/deuterium exchange based mass spectrometry, it was observed that the amino termini of α- and β-globin chains of hemoglobin were involved in the adsorption on NP surface whereas the carboxy termini of both chains became more flexible in its conformation compared to the respective regions of the normal hemoglobin. Circular dichroism spectra of desorbed hemoglobin indicated an adsorption induced localized structural change in the protein molecule. The formation of bioconjugate led to functional alteration of hemoglobin, as probed by oxygen binding assay. Thus, we hypothesize that the large amount of energy released upon adsorption of hemoglobin to NP surface might be the fundamental cause of structural perturbation of human hemoglobin and subsequent formation of the bioconjugate with an altered function.
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http://dx.doi.org/10.1021/acs.langmuir.7b01905 | DOI Listing |
Molecules
January 2025
Department of Chemistry, Technical University of Denmark, 206 Kemitorvet, 2800 Kgs Lyngby, Denmark.
A human epidermal growth factor receptor 2 (HER2)-specific nanobody called 2Rs15d, containing a His3LysHis6 segment at the C-terminus, was recombinantly produced. Subsequent site-selective acylation on the C-terminally activated lysine residue allowed installation of the cytotoxin monomethyl auristatin E-functionalized cathepsin B-sensitive payload to provide a highly homogenous nanobody-drug conjugate (NBC), which demonstrated high potency and selectivity for HER2-positive breast cancer models.
View Article and Find Full Text PDFMany protein bioconjugation strategies focus on the modification of lysine residues owing to the nucleophilicity of their amine side-chain, the generally high abundance of lysine residues on a protein's surface and the ability to form robustly stable amide-based bioconjugates. However, the plethora of solvent accessible lysine residues, which often have similar reactivity, is a key inherent issue when searching for regioselectivity and/or controlled loading of an entity. A relevant example is the modification of antibodies and/or antibody fragments, whose conjugates offer potential for a wide variety of applications.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, 70 Nanyang Drive, Singapore 637457, Singapore.
Afterglow luminescence provides ultrasensitive optical detection by minimizing tissue autofluorescence and increasing the signal-to-noise ratio. However, due to the lack of suitable unimolecular afterglow scaffolds, current afterglow agents are nanocomposites containing multiple components with limited afterglow performance and have rarely been applied for cancer theranostics. Herein, we report the synthesis of a series of oxathiine-containing donor-acceptor block semiconducting polymers (PDCDs) and the observation of their high photoreactivity and strong near-infrared (NIR) afterglow luminescence.
View Article and Find Full Text PDFBioorg Chem
February 2025
Department of Chemistry, Indian Institute of Technology Indore, Indore 453552 India; Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Indore 453552 India. Electronic address:
Prostate cancer (PCa) has emerged to be the second leading cause of cancer-related deaths in men. Molecular imaging of PCa using targeted radiopharmaceuticals specifically to PCa cells promises accurate staging of primary disease, detection of localized and metastasized tumours, and helps predict the progression of the disease. Glutamate urea heterodimers have been popularly used as high-affinity small molecules in the binding pockets of popular and well-characterized PCa biomarker, prostate specific membrane antigen (PSMA).
View Article and Find Full Text PDFJ Fluoresc
January 2025
Department of Medical Biotechnology and Stem Cell and Regenerative Medicine, Centre for Interdisciplinary Research, D. Y. Patil Education Society (Deemed to be University), Kolhapur, Maharashtra, 416 006, India.
Carbon quantum dots (CQDs) demonstrate outstanding biocompatibility and optical properties, making them ideal for monitoring cellular uptake. Due to their ultra-small size (typically < 10 nm) and fluorescent nature, CQDs hold significant potential as nanoparticles for bioimaging and tracking intracellular processes. The study examined the optimization parameters for conjugating calf thymus DNA (Ct-DNA) to CQDs to facilitate Ct-DNA internalization in mouse fibroblast cells (L929) and human breast cancer cells (MCF-7).
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