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Molecular graphics

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Molecular graphics is the scientific discipline of studying molecules through graphical representations. It involves a specific philosophy of using visual tools to understand molecular properties. According to IUPAC, these representations must be shown on a "graphical display device." Because molecules are far too small to see with the naked eye, these graphics are essential. They allow scientists to visualize how atoms are arranged and how they interact.

jmol1
jmol1

There are several distinct ways to represent these structures. The ball-and-stick model uses small spheres to represent atoms. It uses rods to represent the chemical bonds connecting them.

jmol1
jmol1

Another method is the space-filling model. This model draws atoms as solid spheres to suggest the actual space they occupy. This is based on their van der Waals radii, which is the distance where atoms begin to interact. In these models, atoms that share a bond will overlap.

FormicAcid.pdb
FormicAcid.pdb

Scientists also use surface models to show electrostatic potential. These surfaces use colors to show charge density. For example, red areas indicate a net positive charge density. Blue areas indicate a net negative charge density.

Water-elpot-transparent-3D-balls
Water-elpot-transparent-3D-balls

Before computers, scientists used physical models to study molecular structures. Robert Corey and Linus Pauling developed a system using hard wood. They worked at a scale where 1 inch represented 1 angstrom. They used a clamping device to keep the molecular configuration steady. These pioneers also established the CPK coloring scheme. This scheme helps scientists differentiate atom types using color. In this system, carbon is black, oxygen is red, and nitrogen is blue. W.L. Koltun improved these models in 1966, and they are now called Corey-Pauling-Koltun (CPK) models.

Digital molecular graphics began to emerge in the mid-1960s. Project MAC produced the first wire-frame models on a cathode ray tube. In 1965, Carroll Johnson distributed the Oak Ridge thermal ellipsoid plot, or ORTEP. This visualized molecules as ball-and-stick models. It used lines for bonds and ellipsoids to represent the probability of thermal motion. ORTEP became the standard for displaying X-ray crystallography data. In 1966, Cyrus Levinthal and Robert Langridge achieved a milestone. They used a wireframe representation to display the protein myoglobin.

Hemagglutinin molecule
Hemagglutinin molecule

To see depth, researchers often use 3D graphics technology. During the 1970s, scientists developed methods to display 3D graphics on cathode ray tubes. They used continuous tone computer graphics with electro-optic shutter viewing devices. One type is an active shutter 3D system. These systems generate different perspective views for the left and right eye. These active glasses require batteries to work. They use lead lanthanum zirconate titanate (PLZT) ceramics as electronically controlled shutters.

CrystalEyes shutter glasses
CrystalEyes shutter glasses

Many modern systems use passive, polarized 3D glasses. These are less expensive and rely on the wearer's own perception to see 3D effects.

As molecules grew larger, traditional physical model-building could not scale. This drove the need for advanced macromolecular crystallography tools. In 1975, Marge Legg solved a high-resolution structure of staph nuclease using the FIT program. In 1976, Jim Hogle solved the structure of monoclinic lysozyme. Alwyn Jones later developed the FRODO program. This program allowed scientists to overlay molecular electron density with a hypothetical structure. These digital tools replaced the physical Richards' Box for modeling density in 3D.

Molecular graphics connects chemistry to computer science and physics. The field has moved from hand-drawn sketches to high-performance rendering. Nelson Max contributed to this by creating realistic renderings of macromolecules. These renderings use reflecting spheres to improve visual accuracy. Today, the field includes various software platforms. These range from early systems like RasMol to modern browser-based tools. These tools allow scientists to explore the complex shapes of the microscopic world.

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🖼️ Images & Media (6)
Fullerene C60 with isosurface.webm
File:CrystalEyes shutter glasses.jpg
CrystalEyes shutter glasses.jpg
File:jmol1.png
jmol1.png
File:FormicAcid.pdb.png
FormicAcid.pdb.png
File:Water-elpot-transparent-3D-balls.png
Water-elpot-transparent-3D-balls.png
File:Hemagglutinin molecule.png
Hemagglutinin molecule.png
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