Design, synthesis, and crystal structure of self-assembling norbornene (nbe)-supported two-helix bundles: a unique example of janus helicity in the solid-state structure of nbe(aib5)2

Ranganathan, Darshan ; Kurur, Sunita ; Karle, Isabella L. (2000) Design, synthesis, and crystal structure of self-assembling norbornene (nbe)-supported two-helix bundles: a unique example of janus helicity in the solid-state structure of nbe(aib5)2 Biopolymers, 54 (4). pp. 249-261. ISSN 0006-3525

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Official URL: http://onlinelibrary.wiley.com/doi/10.1002/1097-02...

Related URL: http://dx.doi.org/10.1002/1097-0282(20001005)54:4<249::AID-BIP20>3.0.CO;2-N

Abstract

Norbornene-supported bis-helical peptides with the general structure NBE(Aibn)2 (NBE: 2,3-trans-norbornene dicarbonyl unit; Aib: α,α'-dimethyl glycine unit; n = 4,5) have been synthesized and examined for self-assembly preferences in the solid state. An x-ray study has revealed a phenomenon of Janus helicity in the solid state structure of NBE(Aib5)2. The lower homologue NBE(Aib4)2, however, shows an identical screw sense for both the helical arms. The difference in the handedness of left and right arms is reflected in the self-assembly patterns. Thus, while the NBE(Aib4)2 molecule self-assembles to form an infinite hydrogen-bonded superhelical ladder, the Janus molecule NBE(Aib5)2 crystallizes as individual units surrounded by water molecules. The structures of Z–Aib4–OMe and Z–Aib5–OMe are also presented to compare their conformations with the helical arms of the title compound and also to the already known structures of other X–Aibn –Y compounds. The helices in all the molecules are the 310-type.

Item Type:Article
Source:Copyright of this article belongs to John Wiley and Sons, Inc.
Keywords:Helix–water Interactions; Helix Sense; Ladder Assembly; Mixed Helicity; Scaffold
ID Code:35695
Deposited On:05 Jul 2011 11:22
Last Modified:05 Jul 2011 11:22

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