Tag: cryo-electron microscopy

Cryo-electron microscopy has reached resolution on par with X-ray crystallography

February 1, 2024

Compared to the more established X-ray crystallography, cryo-electron microscopy images were of lower resolution until a recent breakthrough that brought forth a “resolution revolution”. Specifically, advances in instrument setup, optics, and reconstruction software helped ushered in a new era in cryo-electron microscopy where resolution of images could reach 1.25 Angstrom. This is similar to that … More Cryo-electron microscopy has reached resolution on par with X-ray crystallography

Cryo-electron microscopy could only output the predominant structure or the structure with the best signal to noise ratio

January 24, 2024

In recent years, cryo-electron microscopy has shown its fortitude in solving an array of increasingly difficult and more complex protein structures. But, is the technique capable of solving all possible conformations of a protein? The answer is no, as cryo-electron microscopy could only output the predominant structure or the structure with the best signal to … More Cryo-electron microscopy could only output the predominant structure or the structure with the best signal to noise ratio

Cryo-electron microscopy is still unable to capture the full motion of an enzyme undergoing catalysis

January 22, 2024

A holy grail in structural biology has been the capturing of movies that depict an enzyme undergoing catalysis, i.e., preferably with the enzyme in motion that captures a substrate, coverts it into a product, and releasing the product. To do so would require a method that could accurately image a protein with high resolution while … More Cryo-electron microscopy is still unable to capture the full motion of an enzyme undergoing catalysis

Experimental structural biology is still needed to verify predictions from computational structural biology

January 9, 2024

Understanding protein structure is fundamental to elucidating its function. But, difficulty in obtaining crystal structure and the sheer number of proteins available in nature meant that there remains a paucity of experimental structures of proteins available in public databases such as the Protein Data Bank. This then drove the development of computational structural biology tools … More Experimental structural biology is still needed to verify predictions from computational structural biology

High energy electrons are needed for rendering high resolution images in cryo-electron microscopy

September 25, 2021

Electrons used in cryo-electron microscopy are typically accelerated to 75% of the speed of light. But, wouldn’t these high energy electrons result in severe damage to the protein sample under imaging? The answer is no if the energy of the electrons is sufficiently high. To better appreciate the phenomenon, it is important to know that … More High energy electrons are needed for rendering high resolution images in cryo-electron microscopy

Cryo-electron microscopy provides critical access to structures of membrane proteins compared to X-ray crystallography

September 11, 2021

Structures of membrane proteins are hard to determine by traditional approaches such as X-ray crystallography. This comes about due to the inherent flexibility of the transmembrane part of the membrane proteins that insert in between the hydrophobic tails of the phospholipid bilayer. While approaches such as stapling the hydrophobic parts of membrane proteins provide a … More Cryo-electron microscopy provides critical access to structures of membrane proteins compared to X-ray crystallography

Advent of direct electron detector revolutionized cryo-electron microscopy

August 29, 2021

Besides sample preparation, detectors are also a critical part of the instrument set-up necessary for carrying out cryo-electron microscopy work. Prior to the advent of direct electron detectors, charge-coupled device (CCD) detectors are the main types of detection methods in use in cryo-electron microscopes around the world. Although able to provide an image from the … More Advent of direct electron detector revolutionized cryo-electron microscopy

Sample preparation remains an art form in cryo-electron microscopy despite the advent of automated tools

August 15, 2021

Cryo-electron microscopy has emerged as the sought after tool in structural biology, largely due to its simplicity in sample preparation. Specifically, protein samples are dipped into liquid ethane to snap-freeze proteins for imaging. This helps reduce the motion of proteins, and thereby, affords more accurate and higher resolution imaging. But, sample preparation remains an art … More Sample preparation remains an art form in cryo-electron microscopy despite the advent of automated tools

Image reconstruction is critical to success of cryo-electron microscopy structure elucidation

August 9, 2021

In cryo-electron microscopy, proteins are frozen in a glassy vitrified aqueous medium that upon illumination with a high energy electron beam, would cast electron diffraction shadows that, in aggregate, help suggest a structure of the protein. This state of affairs is in fact a highly abstract depiction of what happens in cryo-electron microscopy image reconstruction. … More Image reconstruction is critical to success of cryo-electron microscopy structure elucidation

Quality of homology structural model differs but quality of model is better for proteins with many solved experimental structures

July 14, 2021

Experimental structural biology techniques such as X-ray crystallography and cryo-electron microscopy have been the mainstay approaches for providing a view of the structures of many classes and types of protein. With improving instrumentation and enhanced speed for solving protein structures, there is a gradual but steady expansion of the collection of protein structures available in … More Quality of homology structural model differs but quality of model is better for proteins with many solved experimental structures