The orientation of surface-grafted dsDNA assemblies relative to the surface depends strongly on the nature of the employed thiol anchor. This was shown by ssDNA capture probe strands of 20 bases grafted to a gold surface by three dithiane rings or a single mercaptohexyl group. The capture probe strands were hybridized to one end of complementary ssDNA strands (target) comprising 40, 60, or 80 bases (T , T , and T ). At the other end of the targets a fluorophore-labeled reporter probe ssDNA strand of 20 bases was hybridized. To stiffen the DNA assemblies, the targets T and T were further hybridized to ssDNA patches of 20 or 40 bases. Whether the fluorescence intensity, and thus the distance between surface and fluorophore, increases or decreases with increasing target length depends on the thiol anchor. Attempts were made to heal the nicks that are present in the formed dsDNA assemblies by ligation. For enzymatic ligation, the presence of a phosphate at the 5'-end of the reporter probe and a patch is required, which may also influence the fluorescence intensity.
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http://dx.doi.org/10.1002/chem.201604652 | DOI Listing |
Biosensors (Basel)
January 2025
Institute of Biological Information Processing, Bioelectronics (IBI-3), Forschungszentrum Jülich GmbH, 52428 Jülich, Germany.
With the goal of fast and accurate diagnosis of infectious diseases, this study presents a novel electrochemical biosensor that employs a refined aptamer (C9t) for the detection of spike (S) protein SARS-CoV-2 variants in a flexible multielectrode aptasensor array with PoC capabilities. Two aptamer modifications were employed: removing the primer binding sites and including two dithiol phosphoramidite anchor molecules. Thus, reducing fabrication time from 24 to 3 h and increasing the stability and sparseness for multi-thiol aptasensors compared to a standard aptasensor using single thiols, without a reduction in aptamer density.
View Article and Find Full Text PDFInt J Mol Sci
December 2024
Department of Chemistry, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea.
The effect of solution pH on the formation and surface structure of 2-pyrazinethiolate (2-PyzS) self-assembled monolayers (SAMs) formed by the adsorption of 2-mercaptopyrazine (2-PyzSH) on Au(111) was investigated using scanning tunneling microscopy (STM) and X-ray photoelectron microscopy (XPS). Molecular-scale STM observations clearly revealed that 2-PyzS SAMs at pH 2 had a short-range ordered phase of (2√3 × √21)R30° structure with a standing-up adsorption structure. However, 2-PyzS SAMs at pH 8 had a very unique long-range ordered phase, showing a "ladder-like molecular arrangement" with bright repeating rows.
View Article and Find Full Text PDFPLoS Negl Trop Dis
January 2025
Department of Pediatrics, National School of Tropical Medicine, Baylor College of Medicine, Houston, Texas, United States of America.
Background: The antigen Na-GST-1, expressed by the hookworm Necator americanus, plays crucial biochemical roles in parasite survival. This study explores the development of mRNA vaccine candidates based on Na-GST-1, building on the success of recombinant Na-GST-1 (rNa-GST-1) protein, currently assessed as a subunit vaccine candidate, which has shown promise in preclinical and clinical studies.
Methodology/findings: By leveraging the flexible design of RNA vaccines and protein intracellular trafficking signal sequences, we developed three variants of Na-GST-1 as native (cytosolic), secretory, and plasma membrane-anchored (PM) antigens.
Biochemistry
January 2025
Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, United States.
Aspartimidylation is a post-translational modification found in multiple families of ribosomally synthesized and post-translationally modified peptides (RiPPs). We recently reported on the imiditides, a new RiPP family in which aspartimidylation is the class-defining modification. Imiditide biosynthetic gene clusters encode a precursor protein and a methyltransferase that methylates a specific Asp residue, converting it to aspartimide.
View Article and Find Full Text PDFNat Commun
January 2025
Aiiso Yufeng Li Family Department of Chemical and Nano Engineering, University of California San Diego, La Jolla, USA.
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