A. X-Ray
Diffraction (Crystallography):
- a beam of incident X-rays passed thru a crystal
diffracts in many specific directions. By measuring the
angles and intensities of these diffracted beams, a
crystallographer can produce a three-dimensional picture
of the density within the crystal.
B. Cryo-Electron
Microcopy (C-TEM): - samples are
cooled to cryogenic temperatures and embedded in an
environment of vitreous water (amorphous solid
[non-crystalline] form of water produced by rapid
cooling. Narrow e-beams capture each electron in TEM and
software algorithms are used for the determination of
biomolecular structures at near-atomic resolution.
but now -next
C. Artificial Intelligence Computer Software Modeling:
A UK based artificial intelligence company [DeepMind Technologies] was acquired by Google in 2014. Google used it to create artificial intelligence software (Alpha Fold) that solves protein folding structures akin to those by X-ray crystallaography and cryo-electron microscopy.
AlphaFold’s structure predictions were indistinguishable from those determined the ‘gold standard’ methods of X-ray crystallography and cryo-electron microscopy [click on figure below]. AlphaFold might lessen the need for these laborious and expensive methods and AI will make it possible to study living things in new ways. AlphaFold Uses the physical and geometric constraints that determine how a protein folds and comes up with a ‘consensus’ model of what the protein should look like.
Some applications, such as the evolutionary analysis of proteins, are set to flourish because the tsunami of available genomic data might now be reliably translated into structures.
<-- click for animation
a protein's function is determined by its 3D shape