conformation

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conformation

Chem
a. another name for configuration
b. one of the configurations of a molecule that can easily change its shape and can consequently exist in equilibrium with molecules of different configuration

Conformation

 

(of molecules), geometric forms that molecules of organic compounds can assume during the rotation of atoms or groups of atoms (substituents) about single bonds while maintaining the order of the chemical bonding of the atoms (chemical structures), the bond lengths, and valency angles. Molecules that differ from one another only in conformation are called conformers, or rotational isomers. The existence of conformations is determined by the spatial interaction (such as repulsion, attraction, and hydrogen bond formation) of substituents (hydrogen atoms included) that are not bonded to one another. One such example (see Figure 1) is represented by several planar conformations of a pentane molecule:

CH3—CH2—CH2—CH2—CH3

Unlike geometric and optical isomers, conformers under general conditions easily convert into one another (without the breaking of bonds) and therefore cannot be isolated (compareCONFIGURATION). The molecules of organic compounds usually exist in the form of a mixture of conformers that are in equilibrium,

Figure 1. Planar conformations of a pentane molecule: (a) zigzag, (b) claw-shaped, (c) irregular

among which those that are energetically most favorable, that is, exhibiting the lowest energy, predominate. The conformational state of molecules affects the physical properties of substances and the orientation and rate of chemical transformations (see).

V. M. POTAPOV

conformation

[kän·fər′mā·shən]
(organic chemistry)
In a molecule, a specific orientation of the atoms that varies from other possible orientations by rotation or rotations about single bonds; generally in mobile equilibrium with other conformations of the same structure. Also known as conformational isomer; conformer.
References in periodicals archive ?
We can consider that both conformations of the quercetin molecule can occur naturally in a chitosan+quercetin complex because their binding affinities are the most negative.
The trace of the conformation tensor can be related to the mean square chain extension as follows [24]:
Further, HP sequence is used as input to generate the initial conformations. The initial conformations were obtained using the proposed initialization method developed by the hill-climbing algorithm to attain the valid conformation with minimal time and computation.
These correlations can be reduced to a matrix differential equation, and the eigenvalues and eigenvectors of the equation will specify the lowest energy conformation of the molecule being studied.
The stability of the PC dimers was established as a relative value of free energy ([DELTA]E), that is, as the difference in free energy between the lowest-energy dimer and the remaining dimers in their distinct conformations.
In particular, we set out to address key questions concerning sugar pucker conformation, phosphate-phosphate interaction, phosphatebase interaction, and metal ion binding environment around the helical structure.
In this study, the effect of molecular structure on the conformation of polymer molecule adsorbed onto the carbon black particles is investigated.
The database obtained included 118 structures, which represent locally stable glutamate conformations; neither bond lengths nor bond angles are statistically different, and the values are in a close range (0.001 [Angstrom] to 0.02 [Angstrom]) for the bond angles of the 118 glutamate conformers.
Carcass characteristics, carcass conformation, carcass degree of fat cover and rib segment composition were collected on 40 Lagunaire, 71 Borgou and 110 Zebu Fulani bulls.
Use of urea (5M) induced tertiary conformations of these proteins improved sero-detection on immune blots of cysticercus antibodies among patients with solitary cyst infections to 71% from 62% using antigens not treated with urea.
Since the bond angles can range from -180 to +180, there are a number of conformations a protein can undergo.
This is a simplistic model; however, the possible conformations are a little more complex, as shown in Figure 6.