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Myoglobin sketch Alpha helix. 1958 – Myoglobin was the very first crystal structure of a protein molecule. [2] Myoglobin cradles an iron-containing heme group that reversibly binds oxygen for use in powering muscle fibers, and those first crystals were of myoglobin from the sperm whale, whose muscles need copious oxygen storage for deep dives.
A network solid or covalent network solid (also called atomic crystalline solids or giant covalent structures) [1] [2] is a chemical compound (or element) in which the atoms are bonded by covalent bonds in a continuous network extending throughout the material.
For example, while biology refers to macromolecules as the four large molecules comprising living things, in chemistry, the term may refer to aggregates of two or more molecules held together by intermolecular forces rather than covalent bonds but which do not readily dissociate.
Typically, a molecular solid is ductile when it has isotropic intermolecular interactions. This allows for dislocation between layers of the crystal much like metals. [5] [8] [11] For example, plastic crystals are soft, resemble waxes and are easily deformed. One example of a ductile molecular solid, that can be bent 180°, is hexachlorobenzene ...
A crystal's crystallographic forms are sets of possible faces of the crystal that are related by one of the symmetries of the crystal. For example, crystals of galena often take the shape of cubes, and the six faces of the cube belong to a crystallographic form that displays one of the symmetries of the isometric crystal system. Galena also ...
The orientation of crystallites can be random with no preferred direction, called random texture, or directed, possibly due to growth and processing conditions.While the structure of a single crystal is highly ordered and its lattice is continuous and unbroken, amorphous materials, such as glass and many polymers, are non-crystalline and do not display any structures, as their constituents are ...
The crystals are trigonal and chiral (space group 152 or 154 depending on the chirality), like the gray form of selenium. It is a brittle and easily pulverized metalloid. Amorphous tellurium is a black-brown powder prepared by precipitating it from a solution of tellurous acid or telluric acid (Te(OH) 6). [13]
Developing protein crystals is a difficult process influenced by many factors, including pH, temperature, ionic strength in the crystallization solution, and even gravity. [3] Once formed, these crystals can be used in structural biology to study the molecular structure of the protein, particularly for various industrial or medical purposes. [4 ...