Experiments are presented that suggest DNA strands chemically immobilized on gold nanoparticle surfaces can engage in two types of hybridization: one that involves complementary strands and normal base pairing interactions and a second one assigned as a "slipping" interaction, which can additionally stabilize the aggregate structures through non-Watson-Crick type base pairing or interactions less complementary than the primary interaction. The curvature of the particles appears to be a major factor that contributes to the formation of these slipping interactions as evidenced by the observation that flat gold triangular nanoprism conjugates of the same sequence do not support them. Finally, these slipping interactions significantly stabilize nanoparticle aggregate structures, leading to large increases in T(m)'s and effective association constants as compared with free DNA and particles that do not have the appropriate sequence to maximize their contribution.
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http://dx.doi.org/10.1021/nl8030482 | DOI Listing |
Chem Commun (Camb)
January 2025
Department of Chemistry, Bar-Ilan University, Ramat-Gan 5290002, Israel.
Modified nucleosides are vital in mRNA vaccines. We developed a contracted uridine analog, N1-hydantoinyl-ribose, HR, using steric shields to invert the regioselectivity of the classic Vorbrüggen reaction. We report synthetic routes and explore HR features such as acidity, stability, base pairing/stacking, and crystal/solution conformation compared to uridine.
View Article and Find Full Text PDFActa Histochem
January 2025
School of Chemistry, University of Glasgow, Glasgow G12 8QQ, UK.
In recent years, a great interest has been focused on the prebiotic origin of nucleic acids and life on Earth. An attractive idea is that life was initially based on an autocatalytic and autoreplicative RNA (the RNA-world). RNA duplexes are right-handed helical chains with antiparallel orientation, but the rationale for these features is not yet known.
View Article and Find Full Text PDFMikrochim Acta
January 2025
School of Science, Xihua University, Chengdu, 610039, People's Republic of China.
A dual-mode detection platform utilizing colorimetric and Raman was developed based on the exponential amplification reaction (EXPAR) strategy and a "core-satellite" structure constructed by bimetallic nanozymes to detect chloramphenicol (CAP). Initially, DNA-gated metal-organic frameworks (MOFs) incorporating cascaded amplification were used to be nanocarriers for the colorimetric and Raman reporter molecules (3,3',5,5'-tetramethylbiphenyl; TMB). Subsequently, assembled DNA served as gatekeepers to create a stimulus-responsive DNA-gated MOF (TMB@DNA/MOF).
View Article and Find Full Text PDFNucleic Acids Res
January 2025
Advanced Analysis Data Center, Korea Institute of Science and Technology, Hwarang-ro 14-5, Seongbuk-gu, Seoul 02792, Republic of Korea.
Riboswitches are RNAs that recognize ligands and regulate gene expression. They are typically located in the untranslated region of bacterial messenger RNA and consist of an aptamer and an expression platform. In this study, we examine the folding pathway of the Vc2 (Vibrio cholerae) riboswitch aptamer domain, which targets the bacterial secondary messenger cyclic-di-GMP.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125.
From RNA interference to chromatin silencing, diverse genome defense pathways silence selfish genetic elements to safeguard genome integrity. Despite their diversity, different defense pathways share a modular organization, where numerous specificity factors identify diverse targets and common effectors silence them. In the PIWI-interacting RNA (piRNA) pathway, target RNAs are first identified by complementary base pairing with piRNAs and then silenced by PIWI-clade nucleases.
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