Allosteric Regulation of Unidirectional Spring-like Motion of Double-Stranded Helicates

作者：Suzuki Yoshimasa; Nakamura Taiki; Iida Hiroki; Ousaka Naoki; Yashima Eiji^*

来源：Journal of the American Chemical Society, 2016, 138(14): 4852-4859.

DOI：10.1021/jacs.6b00787

We report the unprecedented allosteric regulation of the extension and contraction motions of double stranded spiroborate helicates composed of 4,4'-linked 2,2'-bipyridine (bpy) and its N,N'-dioxide units in the middle of ortho-linked tetraphenol strands. NMR and circular dichroism measurements and an X-ray crystallographic analysis along with theoretical calculations revealed that enantiomeric helicates contract and extend upon the binding and release of protons and/or metal ions at the covalently linked two binding bpy or N,N'-dioxide moieties without racemization, respectively, regulated by a cooperative anti-syn conformational change of the two bpy or N,N'-dioxide moieties. These anti-syn conformational changes that occurred at the linkages are amplified into a large-scale molecular motion of the helicates leading to reversible spring-like motions coupled with twisting in one direction in a highly homotropic allosteric fashion.

• 出版日期2016-4-13