Helix generation

Figure 5. Molecular drawings of a) one single strand of an amylosic chain in the left-handed conformation, having a six-fold symmetry, repeating in 2.1 nm. b) the double-helix generated by the association of two single strands, through two-fold symmetry operation, c) and d) Space-filling plots of the double helix, projected along and perpendicular to the fiber axis, respectively.

Helix Generation, Amplification, Switching, and Memory of Chromophoric Polymers... 

Fricke M, Volkmer D (2007) Crystallization of Calcium Carbonate Beneath Insoluble Mono-layers Suitable Models of Mineral-Matrix Interactions in Biomineralization 270 1-41 FujikiM (2008) Helix Generation, Amplification, Switching, and Memory of Chromophoric Polymers. 284 119-186 Fujimoto D, see Tamura R (2007) 269 53-82... 

From the investigations on APhe-based peptides, it is clear that the 3-D disposition largely preferred by this residue is the hehcal conformation (23, 24). Therefore, most corner positions of the various types of fi-turns and aU positions of 3io-/a-helices are accessible easily to this residue. Fig. (4) shows the right-handed 310-helix generated by a double repetition of the model triplet -(A Phe-A Phe-L-Ala)-. Aromatic amino acid residues, which include A Phe (25), are known to... 

Fig. 1.4 Comparison of the alpha-helix formed by polypeptides (left) with a 3.5 helix generated by an isotactic polymer (right). (From Natta and Corradini (22))...

For additional assessment of binding, we determined by CD whether exposure of CA to LPS produced changes in the secondary structure of CA. The CD spectrum of CA was consistent with an absence of helical conformational modes (Fig. 1). In the presence of 3.5 moles of LPS per mole of CA, however, CA assumed a conformation with 44.8% helix ( 222 = -1.59 X 10" deg cm dmoL ). A conformational change of this magnitude shows unequivocally that CA interacted with LPS. The interaction produced helical coiling in CA similar in extent to the 50% helix generated by dissolution in trifluoroethanol (Merrifield et al., 1982). Virtually identical spectra were obtained with other sources of LPS (data not shown). 

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