An electron microscope is a microscope that uses a beam of electrons as a source of illumination. They use electron optics that are analogous to the glass lenses of an optical light microscope to control the electron beam, for instance focusing them to produce magnified images or electron diffraction patterns. As the wavelength of an electron can be up to 100,000 times smaller than that of visible light, electron microscopes have a much higher resolution of about 0.1 nm, which compares to about 200 nm for light microscopes. Electron microscope may refer to:
Structural biology, as defined by the Journal of Structural Biology, deals with structural analysis of living material at every level of organization.
An X-ray microscope uses electromagnetic radiation in the X-ray band to produce magnified images of objects. Since X-rays penetrate most objects, there is no need to specially prepare them for X-ray microscopy observations.
The Max Planck Institute of Biochemistry is a research institute of the Max Planck Society located in Martinsried, a suburb of Munich. The institute was founded in 1973 by the merger of three formerly independent institutes: the Max Planck Institute of Biochemistry, the Max Planck Institute of Protein and Leather Research, and the Max Planck Institute of Cell Chemistry.
Transmission electron cryomicroscopy (CryoTEM), commonly known as cryo-EM, is a form of cryogenic electron microscopy, more specifically a type of transmission electron microscopy (TEM) where the sample is studied at cryogenic temperatures. Cryo-EM, specifically 3-dimensional electron microscopy (3DEM), is gaining popularity in structural biology.
Cryogenic electron tomography (cryoET) is an imaging technique used to reconstruct high-resolution (~1–4 nm) three-dimensional volumes of samples, often biological macromolecules and cells. cryoET is a specialized application of transmission electron cryomicroscopy (CryoTEM) in which samples are imaged as they are tilted, resulting in a series of 2D images that can be combined to produce a 3D reconstruction, similar to a CT scan of the human body. In contrast to other electron tomography techniques, samples are imaged under cryogenic conditions. For cellular material, the structure is immobilized in non-crystalline, vitreous ice, allowing them to be imaged without dehydration or chemical fixation, which would otherwise disrupt or distort biological structures.
Molecular biophysics is a rapidly evolving interdisciplinary area of research that combines concepts in physics, chemistry, engineering, mathematics and biology. It seeks to understand biomolecular systems and explain biological function in terms of molecular structure, structural organization, and dynamic behaviour at various levels of complexity. This discipline covers topics such as the measurement of molecular forces, molecular associations, allosteric interactions, Brownian motion, and cable theory. Additional areas of study can be found on Outline of Biophysics. The discipline has required development of specialized equipment and procedures capable of imaging and manipulating minute living structures, as well as novel experimental approaches.
Resolution in the context of structural biology is the ability to distinguish the presence or absence of atoms or groups of atoms in a biomolecular structure. Usually, the structure originates from methods such as X-ray crystallography, electron crystallography, or cryo-electron microscopy. The resolution is measured of the "map" of the structure produced from experiment, where an atomic model would then be fit into. Due to their different natures and interactions with matter, in X-ray methods the map produced is of the electron density of the system, whereas in electron methods the map is of the electrostatic potential of the system. In both cases, atomic positions are assumed similarly.
Cryofixation is a technique for fixation or stabilisation of biological materials as the first step in specimen preparation for the electron microscopy and cryo-electron microscopy. Typical specimens for cryofixation include small samples of plant or animal tissue, cell suspensions of microorganisms or cultured cells, suspensions of viruses or virus capsids and samples of purified macromolecules, especially proteins.
Single particle analysis is a group of related computerized image processing techniques used to analyze images from transmission electron microscopy (TEM). These methods were developed to improve and extend the information obtainable from TEM images of particulate samples, typically proteins or other large biological entities such as viruses. Individual images of stained or unstained particles are very noisy, and so hard to interpret. Combining several digitized images of similar particles together gives an image with stronger and more easily interpretable features. An extension of this technique uses single particle methods to build up a three-dimensional reconstruction of the particle. Using cryo-electron microscopy it has become possible to generate reconstructions with sub-nanometer resolution and near-atomic resolution first in the case of highly symmetric viruses, and now in smaller, asymmetric proteins as well. Single particle analysis can also be performed by inductively coupled plasma mass spectrometry (ICP-MS).
David S. Goodsell, is an associate professor at the Scripps Research Institute and research professor at Rutgers University, New Jersey. He is especially known for his watercolor paintings of cell interiors.
In molecular biology, the term macromolecular assembly (MA) refers to massive chemical structures such as viruses and non-biologic nanoparticles, cellular organelles and membranes and ribosomes, etc. that are complex mixtures of polypeptide, polynucleotide, polysaccharide or other polymeric macromolecules. They are generally of more than one of these types, and the mixtures are defined spatially, and with regard to their underlying chemical composition and structure. Macromolecules are found in living and nonliving things, and are composed of many hundreds or thousands of atoms held together by covalent bonds; they are often characterized by repeating units. Assemblies of these can likewise be biologic or non-biologic, though the MA term is more commonly applied in biology, and the term supramolecular assembly is more often applied in non-biologic contexts. MAs of macromolecules are held in their defined forms by non-covalent intermolecular interactions, and can be in either non-repeating structures, or in repeating linear, circular, spiral, or other patterns. The process by which MAs are formed has been termed molecular self-assembly, a term especially applied in non-biologic contexts. A wide variety of physical/biophysical, chemical/biochemical, and computational methods exist for the study of MA; given the scale of MAs, efforts to elaborate their composition and structure and discern mechanisms underlying their functions are at the forefront of modern structure science.
Structural chemistry is a part of chemistry and deals with spatial structures of molecules and solids. For structure elucidation a range of different methods is used. One has to distinguish between methods that elucidate solely the connectivity between atoms (constitution) and such that provide precise three dimensional information such as atom coordinates, bond lengths and angles and torsional angles.
Cryogenic electron microscopy (cryo-EM) is a cryomicroscopy technique applied on samples cooled to cryogenic temperatures. For biological specimens, the structure is preserved by embedding in an environment of vitreous ice. An aqueous sample solution is applied to a grid-mesh and plunge-frozen in liquid ethane or a mixture of liquid ethane and propane. While development of the technique began in the 1970s, recent advances in detector technology and software algorithms have allowed for the determination of biomolecular structures at near-atomic resolution. This has attracted wide attention to the approach as an alternative to X-ray crystallography or NMR spectroscopy for macromolecular structure determination without the need for crystallization.
Bridget Olivia Carragher is a South African physicist specialized in electron microscopy.
Carolyn Larabell is an American scientist that led the first construction and commissioning of a soft x-ray microscope to be used for biological imaging Her research primarily focuses on X-ray microtomography, a technology that allows for a 3D visualization of different cells. Larabell is a joint anatomy professor at the University of California, San Francisco and both the founder and director of the National Center for X-ray Tomography.
Elizabeth Villa is an American biophysicist who is Associate Professor at the University of California, San Diego. Her research considers the development of Cryo Electron Tomography and structural biology. She was named a Howard Hughes Medical Institute Research Investigator in 2021.
Cryomicroscopy is a technique in which a microscope is equipped in such a fashion that the object intended to be inspected can be cooled to below room temperature. Technically, cryomicroscopy implies compatibility between a cryostat and a microscope. Most cryostats make use of a cryogenic fluid such as liquid helium or liquid nitrogen. There exists two common motivations for performing a cryomicroscopy. One is to improve upon the process of performing a standard microscopy. Cryogenic electron microscopy, for example, enables the studying of proteins with limited radiation damage. In this case, the protein structure may not change with temperature, but the cryogenic environment enables the improvement of the electron microscopy process. Another motivation for performing a cryomicroscopy is to apply the microscopy to a low-temperature phenomenon. A scanning tunnelling microscopy under a cryogenic environment, for example, allows for the studying of superconductivity, which does not exist at room temperature.
Julia Mahamid is a cell biologist, structural biologist, and electron microscopist at the European Molecular Biology Laboratory in Heidelberg, Germany, who utilizes biomolecular condensates and advanced cellular cryo-electron tomography to enhance the comprehension of the functional organization of the cytoplasm. She leads the Mahamid Group.
Virus crystallisation is the re-arrangement of viral components into solid crystal particles. The crystals are composed of thousands of inactive forms of a particular virus arranged in the shape of a prism. The inactive nature of virus crystals provide advantages for immunologists to effectively analyze the structure and function behind viruses. Understanding of such characteristics have been enhanced thanks to the enhancement and diversity in crystallisation technologies. Virus crystals have a deep history of being widely applied in epidemiology and virology, and still to this day remains a catalyst for studying viral patterns to mitigate potential disease outbreaks.
