Naturally occurring three-dimensional structure

Figure 4.28 The nautilus is an example of a naturally occurring three-dimensional spiroid structure. The distance between the turns increases from the inside to the outside.

Examine actual three-dimensional structures for the twc enantiomers of carvone. One occurs naturally in carawa> while the other is found in spearmint oil, and are responsible for the characteristic odors of these materials. Determine which form, R or S, is responsible for which odor. 

Elucidation of the three-dimensional structures of / -structural fibrous proteins has attracted the interest of scientists for more than 50 years. In the early days, the objects of these studies were predominandy the naturally occurring fibrous assemblies obtained from jS-silk and stretched mammalian... 

Viswanadhan, V.N., Ghose, A.K., Revankar, G.R., and Robins, R.K. Atomic physiochemical parameters for three dimensional structure directed quantitative structure-activity relationships. 4. Additional parameters for hydrophobic and dispersive interactions and their application for an automated superposition of certain naturally occurring nucleoside antibiotics, / Chem. Inf. Comput. Scl, 29(3) 163-172, 1989. 

Abstract The last few years have seen a considerable increase in our understanding of catalysis by naturally occurring RNA molecules, called ribozymes. The biological functions of RNA molecules depend upon their adoption of appropriate three-dimensional structures. The structure of RNA has a very important electrostatic component, which results from the presence of charged phosphodiester bonds. Metal ions are usually required to stabilize the folded structures and/or catalysis. Some ribozymes utilize metal ions as catalysts while others use the metal ions to maintain appropriate three-dimensional structures. In the latter case, the correct folding of the RNA structures can perturb the pKa values of the nucleo-tide(s) within a catalytic pocket such that they act as general acid/base catalysts. The various types of ribozyme exploit different cleavage mechanisms, which depend upon the architecture of the individual ribozyme. 

Viswanadhan, V. N., et al.. Atomic Physicochemical Parameters for Three Dimensional Structure Directed Quantitative Structure-Activity Relationships IV. Additional Parameters for Hydrophobic and Dispersive Interaction and Their Application for an Automated Superposition of Certain Naturally Occurring Nucleoside Antibiotics. J. Chem. Inf. Comput. Sci., 1989 29, 163-172. 

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