Molecular graphics
Discipline of studying molecules through graphical representation.
Molecular graphics is the discipline and philosophy of studying molecules and their properties through graphical representation. IUPAC limits the definition to representations on a 'graphical display device'. Ever since Dalton's atoms and Kekulé's benzene, there has been a rich history of hand-drawn atoms and molecules, and these representations have had an important influence on modern molecular graphics. Colour molecular graphics are often used on chemistry journal covers artistically.
- field
- Molecular graphics
- known_for
- Graphical representation of molecules, including ball-and-stick models, space-filling models, surfaces, and ribbon diagrams
Lore & Background
Prior to the use of computer graphics in representing molecular structure, Robert Corey and Linus Pauling developed a system for representing atoms or groups of atoms from hard wood on a scale of 1 inch = 1 angstrom connected by a clamping device to maintain the molecular configuration. These early models also established the CPK coloring scheme that is still used today to differentiate the different types of atoms in molecular models (e.g. carbon = black, oxygen = red, nitrogen = blue, etc). Koltun and are now known as Corey-Pauling-Koltun (CPK) models. The earliest efforts to produce models of molecular structure was done by Project MAC using wire-frame models displayed on a cathode ray tube in the mid 1960s. Thermal ellipsoid plots quickly became the de facto standard used in the display of X-ray crystallography data, and are still in wide use today. During the 1970s, methods for displaying 3D graphics using cathode ray tubes were developed using continuous tone computer graphics in combination with electro-optic shutter viewing devices. The first devices used an active shutter 3D system, generating different perspective views for the left and right channel to provide the illusion of three-dimensional viewing. Stereoscopic viewing glasses were designed using lead lanthanum zirconate titanate (PLZT) ceramics as electronically controlled shutter elements. Active 3D glasses require batteries and work in concert with the display to actively change the presentation by the lenses to the wearer's eyes. Many modern 3D glasses use a passive, polarized 3D system that enables the wearer to visualize 3D effects based on their own perception.
Reader's Guide
Molecular graphics has been essential for understanding molecular structure, particularly in macromolecular crystallography where traditional physical model-building could not scale. The first two protein structures solved by molecular graphics without the aid of the Richards' Box were built with Stan Swanson's program FIT on the Vector General graphics display in the laboratory of Edgar Meyer at Texas A&M University: First Marge Legg in Al Cotton's lab at A&M solved a second, higher-resolution structure of staph. Alwyn Jones' FRODO program (and later 'O') were developed to overlay the molecular electron density determined from X-ray crystallography and the hypothetical molecular structure. Among the milestones in high-performance molecular graphics was the work of Nelson Max in 'realistic' rendering of macromolecules using reflecting spheres. The discipline continues to provide visual frameworks such as ribbon diagrams, which are schematic representations of protein structure showing the overall path and organization of the protein backbone in 3D, and serve as a visual framework on which to hang details of the full atomic structure.
Did You Know?
- The CPK coloring scheme, still used today, was established by Robert Corey and Linus Pauling's early wooden models.
- Active 3D glasses for molecular graphics used PLZT ceramics as electronically controlled shutter elements.
More in Chemical Bonding And Structure 1-21
Spotted an error? Know more?
This is a living reference — every entry is fact-audited, and reader corrections feed straight into our audit queue. Suggest an edit · See this site's audit record