Amazing stuff!
"There’s a reason AlphaFold—an AI that solves protein structures—garnered a Nobel this year. Understanding where atoms are within a protein is really important for figuring out how that protein works and what’s happened when something goes wrong. But while AlphaFold makes increasingly intelligent guesses, scientists need ways of validating those predictions—that is to say, determining the positions of pieces directly. Enter MINFLUX: a new system for measuring the distances between molecules.
The method works by attaching fluorescent molecules to two places on a protein. When they glow, it's possible to figure out the distance between them. And they can get really precise: down to a separation of just 0.1 nanometers, which is roughly the width of a single atom, or as wide as 12 nanometers. The large range makes the tool very flexible.
But measuring fluorescence isn’t the whole story. The team also employed cutting edge microscopes to make their light-up ruler as accurate as possible. “The new technique is definitely a technical advance,” structural biologist Jonas Ries tells New Scientist. “I don’t know how they got their microscopes so stable.”"
From the significance and abstract:
"Editor’s summary
Measuring distances directly at the nanometer scale is a challenge for optical techniques, even for those using subdiffraction-resolution fluorescence microscopy. Sahl et al. refined an optical approach called MINFLUX such that they could measure precise intramolecular distances in the 1- to 10-nanometer range and below 1 nanometer for molecules with a tilt. Using a polyproline ruler, the authors demonstrate resolution of fluorophores with known single-digit nanometer spacing. They applied this approach to inter- and intramacromolecular measurements of proteins labeled with photoactivatable dyes, including distances too short for current indirect methods. Imaging experiments demonstrated the potential of this technique to study protein-protein interactions in cells. ...
Abstract
Optical investigations of nanometer distances between proteins, their subunits, or other biomolecules have been the exclusive prerogative of Förster resonance energy transfer (FRET) microscopy for decades. In this work, we show that MINFLUX fluorescence nanoscopy measures intramolecular distances down to 1 nanometer—and in planar projections down to 1 angstrom—directly, linearly, and with angstrom precision. Our method was validated by quantifying well-characterized 1- to 10-nanometer distances in polypeptides and proteins. Moreover, we visualized the orientations of immunoglobulin subunits, applied the method in human cells, and revealed specific configurations of a histidine kinase PAS domain dimer. Our results open the door for examining proximities and interactions by direct position measurements at the intramacromolecular scale."
"
- MINFLUX microscopy can pinpoint fluorescent markers at distances down to 1 nanometer with Ångström precision and thus be used to measure the arrangement of subunits in individual macromolecules.
- MINFLUX therefore reaches the distance range that was previously the prerogative of the Förster resonance energy transfer method (FRET), and even goes beyond it.
- MINFLUX expands the repertoire of structural biology methods for studying proteins and other biomolecules and their interactions.
..."
Intra-molecular distances in biomolecules measured optically with Ångström precision (original news release) "A team led by physicists Steffen Sahl and Stefan Hell at the Max Planck Institute (MPI) for Multidisciplinary Sciences in Göttingen and the MPI for Medical Research in Heidelberg has succeeded in measuring distances within biomolecules using a light microscope, down to 1 nanometer and with Ångström precision. The intra-molecular resolution achieved with MINFLUX microscopy makes it possible to optically record the spatial distances between subunits in macromolecules and thus to detect different conformations of individual proteins in the light microscope (Science, October 11, 2024)."
Polyprolines of different lengths, relatively stiff polypeptides, served as intramolecular “nanometer rulers” to demonstrate the highest MINFLUX resolutions in the Förster resonance energy transfer (FRET) distance range. The 2-sigma ellipses show the measurement uncertainty of the individual positions.
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