NMR is a powerful biophysical tool to ascertain atomic resolution details of a macromolecule. It relies upon the basic quantum mechanical property of nuclear spins. Atoms with nonzero spin numbers, when placed in a magnetic field, are at different energy levels. We can stimulate and follow transitions between these levels at specific resonance frequencies. The most prominent feature of NMR spectroscopy is its ability to differentiate chemically identical atoms, experiencing small variations in their magnetic environment influenced by its neighboring atoms. This property, substantiated by half a century of scientific and technological developments, allows for the assignment of each peak in the spectrum to a specific atom within a molecule of interest. Delineating a macromolecule's structure can be broadly split into identifying the atoms and their three-dimensional position with respect to each other. Nuclear Overhauser effect (NOE) provides the main source of geometric information utilized for structure determination by NMR, and requires the assignment of each proton resonance in a spectrum of the target molecule. For small molecules of a hundred residues or less, this could be accomplished through conventional homonuclear 1H two-dimensional (2D) experiments developed in the late 1970s and early 1980s. For larger molecules, overlapping chemical shifts and increases in linewidth (due to increased rotational correlation time, τc), greatly complicates spectral analysis demanding an improvement of spectral resolution. NMR data often produces a "blurred" image of a macromolecule, composed by different models that resemble the dynamic state of the macromolecule in solution. Here you have a example of NMR-determined structure of a portion of centromeric DNA (PDB code: 2MRZ)

#molecularart ... #nmr ... #dna ... #model ... #solution ... #blurred

Structure rendered with @proteinimaging, post-processed with @stylar.ai_official and depicted with @corelphotopaint