Chain-folding principle

A path with a lower positive free-enthalpy barrier to crystallization than to the extended-chain crystals involves ufolded-chain macroconformation and leads to the chain-folding principle. Crystallization occurs first with shorter, chain-folded segments of the molecules, as shown schematically at B of Fig. 5.42 (A B). From... 

Fig. 3.1. Illustration to the chain-folding principle of pol5mier crystallization. The metastable chain-folding is a favorite pathway in the kinetic selections of polymer crystal nucleation...

Chain Folding Principle and Single Crystal Sectorization. How can... 

Figure 3. Schematic representation of a polymer single crystal, illustrating the principle of chain folding (13)...

Schultz GE, Shrimer RH. Patterns of folding and association of polypeptide chains. In Principles of Protein Structure, New York Springer-Verlag 1979 Chapter 5, 66-107. 

A basic principle of protein chemistry is the central relationship between three-dimensional structure and activity. Unless the linear polypeptide chain folds into a particular three-dimensional configuration, the protein is inactive. As Fig. 2 illustrates, the active form of a protein is typically a highly convoluted, globular structure in which a particular small domain is the precise locus of interaction with reactant or binding ligand. 

FIGURE 11.8 Fully-developed spherulite grown from the melt, comprising chain-folded lamellae (magnified section) and branching points that help to impart a spherical shape to the structure. Most rapid growth occurs in the direction of the spherulite radius R. (Adapted from McCrum, N.B., Buckley, C.P., and Bucknall, C.B., Principles of Polymer Engineering, Oxford University Press, 1988. With permission.)... 

The double-stranded DNA consists of two parallel chains folded into an a-helix. The chains are joined by hydrogen bonds that follow the rules of complementarity. In accordance with these rules, adenine is always bound with thymine of the other chain and guanine is always bound to cytosine (see the following scheme). The principles of molecular complementarity do not apply only to nucleic acids. Rather, they represent general rules for the formation of various supramolecular structures. If nucleotides are labeled by their first letters, the complementary pairs would be AT and GC, respectively. The structural key for complementarity is the number of hydrogen bonds. There are two such bonds in the AT pair and three in... 

A core assumption when discussing the crystallization kinetics of polymers is that the theories must consider the effects of chain folding. In Chapter 2 the principles of crystallization were outlined and the importance of the differences... 

The Hoffman-Lauritzen spherulitie growth rate equation (Al) is similar in principle to the Becker-Doring model (except for the complexions that are invoked to incorporate chain folding). The basic equation ean be represented formally by... 

CB Anfinsen. Principles that govern the folding of protein chains. Science 181 223-238, 1973. 

The folding of a single polypeptide chain in three-dimensional space is referred to as its tertiary structure. As discussed in Section 6.2, all of the information needed to fold the protein into its native tertiary structure is contained within the primary structure of the peptide chain itself. With this in mind, it was disappointing to the biochemists of the 1950s when the early protein structures did not reveal the governing principles in any particular detail. It soon became apparent that the proteins knew how they were supposed to fold into tertiary... 

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