Conformations and cryo-force spectroscopy of spray-deposited single-strand DNA on gold.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 30737410.
- Also identified by DOI 10.1038/s41467-019-08531-4 and PMC identifier 6368621.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Cryo-electron microscopy can determine the structure of biological matter in vitrified liquids. However, structure alone is insufficient to understand the function of native and engineered biomolecules. So far, their mechanical properties have mainly been probed at room temperature using tens of pico-newton forces with a resolution limited by thermal fluctuations. Here we combine force spectroscopy and computer simulations in cryogenic conditions to quantify adhesion and intra-molecular properties of spray-deposited single-strand DNA oligomers on Au(111). Sub-nanometer resolution images reveal folding conformations confirmed by simulations. Lifting shows a decay of the measured stiffness with sharp dips every 0.2-0.3 nm associated with the sequential peeling and detachment of single nucleotides. A stiffness of 30-35 N m<sup>-1</sup> per stretched repeat unit is deduced in the nano-newton range. This combined study suggests how to better control cryo-force spectroscopy of adsorbed heterogeneous (bio)polymer and to potentially enable single-base recognition in DNA strands only few nanometers long.
Medical subject headings
- Cryoelectron Microscopy
- DNA, Single-Stranded
- Gold