Light-dependent regulation of structural flexibility in a photochromic fluorescent protein

Hideaki Mizuno, Tapas Kumar Mal, Markus Wälchli, Akihiro Kikuchi, Takashi Fukano, Ryoko Ando, Jeyaraman Jeyakanthan, Junichiro Taka, Yoshitsugu Shiro, Mitsuhiko Ikura, Atsushi Miyawaki

Research output: Contribution to journalArticlepeer-review

133 Scopus citations


The structural basis for the photochromism in the fluorescent protein Dronpa is poorly understood, because the crystal structures of the bright state of the protein did not provide an answer to the mechanism of the photochromism, and structural determination of the dark state has been elusive. We performed NMR analyses of Dronpa in solution at ambient temperatures to find structural flexibility of the protein in the dark state. Light-induced changes in interactions between the chromophore and β-barrel are responsible for switching between the two states. In the bright state, the apex of the chromophore tethers to the barrel by a hydrogen bond, and an imidazole ring protruding from the barrel stabilizes the plane of the chromophore. These interactions are disrupted by strong illumination with blue light, and the chromophore, together with a part of the β-barrel, becomes flexible, leading to a nonradiative decay process.

Original languageEnglish (US)
Pages (from-to)9227-9232
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number27
StatePublished - Jul 8 2008

All Science Journal Classification (ASJC) codes

  • General


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