Globule formation

Yoshikawa, K. and Matsuzawa, Y. (1995) Discrete phase transition of giant DNA Dynamics of globule formation from a single molecular chain. Physica D, 84, 220-227. 

Fig. 14 Typical core-shell microsegregated structure that is obtained via conformation-dependent copolymerization with simultaneous globule formation in a selective solvent [76]. Hydrophobic chain segments are shown in dark gray and hydrophilic segments are shown in light gray...

Figure 6 Schematic representation of major ampullate gland (a). The various parts of the gland and their function, as well as the structure of silk under each part, are shown (Lewis, 2006). Also shown is a model of chain folding, micelle formation, globule formation and curing, and shear processing of silk proteins. This model is motivated by experiments in vitro (Jin and Kaplan, 2003) (b).

One major obstacle to molecular studies in the area of milk-fat globule formation and secretion is the lack of a cell line that secretes, or can be induced to secrete, milk fat globules, although some progress in this area has been reported (Rohlfs et al, 1993). Development of such a cell line would be a major advance, in and of itself, and would be an invaluable aid in fostering further research in this area. 

Procedure Transfer 3.00 g of sample into a round-bottom, 100-mL boiling flask provided with a ground-glass joint, add 30 mL of the Saponifying Solution, attach a reflux condenser to the flask, and heat the mixture gently on a steam bath for 2 h. At the end of this period, remove the reflux condenser, insert a thermometer into the solution, and place the flask in an 80° water bath. Rotate the flask while both the bath and the solution cool to 65°. The solution shows no cloudiness or globule formation before this temperature is reached. 

In the course of conformational transition the number g of monomer units forming the electrostatic blob increases. For the case of relatively short chain (small value of m) or relatively weak degree of ionization / the collapse transition is ended by the formation of spherical globules. The condition for spherical globule formation is... 

Figure 9.2.10 summarizes the approximate geometrical shapes of proteins for hypothetical ideal proteins made of 300 amino acids. The longest structures are always helical. Sheet or globule formation as well as coiling leads to much shorter extensions. 

Polymer chains in multicomponent solvents, when globule formation can be achieved by the re-distribution of solvent components between the globule interior and the outer solution. 

Schematic representation of alternative pathways for connected globule formation during curing of PES/DGEBA.

Fig. 10 (a) Using molecular dynamics, protein-like peptoid sequences were obtained by iterative process of globule formation and addition/redistribution of polar residues on the globule surface, (b) Globule-to-coil transition was induced by titration with acetonitrile, which leads to unfolding of the globules, (c) The transition is more pronounced and sharper in the case of the protein-like sequence. Reproduced from [93], with permission from American Oiemical Society... 

Fig. 2. The three stages of the fusion and flow process (initial movements, smoothing Tgi, globule formation and TJ) in anionic PS samples as a function of reciprocal M . For background discussion on the use of the terms isoviscous state, iso surface tension state, and annealing, see ref. 3.

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