Retinal is the molecule found in photoreceptor cells that undergoes a change in shape when it absorbs light. Specifically, the cis/trans isomerization of a carbon–carbon double bond in this chromophore sets in motion the chain of biochemical processes responsible for vision1,2,3. Here, we obtain atomically resolved images of individual structural isomers of the retinal chromophore attached to C60 molecules and study their dynamic behaviour inside a confined space—that is, inside single-walled carbon nanotubes—using high-resolution transmission electron microscopy (HR-TEM). Sequential HR-TEM images with sub-second time resolution directly reveal the isomerization between the cis and all-trans forms of retinal, as well as conformational changes and volume-conserving effects. This work opens up the possibility of investigating in vitro the biological activities of these photoresponsive molecules on an individual basis, and the molecular imaging technique described here is a general one that can be applied to a wide range of systems.
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Zechmeister, L. in Cis–trans Isomeric Carotenoids, Vitamin A, and Aryl Polyenes (Academic Press, New York, 1962).
Spudich, J. L., Yang, C., Jung, K. & Spudich, E.N. Retinylidene proteins: Structures and functions from archaea to humans. Annu. Rev. Cell Dev. Biol. 16, 365–392 (2000).
Pebay-Peyroula, E., Rummel, G., Rosenbusch, J. & Landau, E. M. X-ray structure of bacteriodhodopsin at 2.5 angstroms from microscrystals grown in lipid cubic phases. Science 277, 1676–1681 (1997).
Liu, Z. et al. Transmission electron microscopy imaging of individual functional groups of fullerene derivatives. Phys. Rev. Lett. 96, 088304 (2006).
Koshino, M. et al. Imaging of single organic molecules in motion. Science 316, 853 (2007).
Suenaga, K. et al. Element selective single atom imaging. Science 290, 2280–2282 (2000).
Hirahara, K. et al. Electron diffraction study of one-dimensional crystals of fullerenes. Phys. Rev. B 64, 115420 (2001).
Liu, R. S. H. Photoisomerization by Hula-twist. Photoactive biopigments. Pure Appl. Chem. 74, 1391–1396 (2002).
Reimer, L. in Physical Aspects of Electron Microscopy and Microbeam Analysis (ed. Siegel, B. M. & Beaman, D. R.) 231–245 (Wiley, New York, 1975).
Egerton, R., Li, P. & Malac, M. Radiation damage in the TEM and SEM. Micron 35, 399–409 (2004).
Kobayashi, T., Saito, T. & Ohtani, H. Real-time spectroscopy of transition states in bacteriorhodopsin during retinal isomerization. Nature 414, 531–534 (2001).
Yamazaki, M., Araki, Y., Fujitsuka, M. & Ito, O. Photoinduced microsecond-charge-separation in retinyl-C60 dyad. J. Phys. Chem. A 105, 8615–8622 (2001).
Kataura, H. et al. High-yield fullerene encapsulation in single-wall carbon nanotubes. Synth. Met. 121, 1195–1196 (2001).
Kirkland, E. J. in Advanced Computing in Electron Microscopy, 106–117 (Plenum Press, New York, 1998).
Work on electron microscopy was supported by CREST. K.Y. thanks M. Funabashi for his help in a mass spectroscopy experiment. The partial support of a Grant-in-Aid for Scientific Research from MEXT is also acknowledged by K.Y. and H.K.
The authors declare no competing financial interests.
Supplementary figures S1 and S2, and captions to supplementary movies (PDF 395 kb)
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Liu, Z., Yanagi, K., Suenaga, K. et al. Imaging the dynamic behaviour of individual retinal chromophores confined inside carbon nanotubes. Nature Nanotech 2, 422–425 (2007). https://doi.org/10.1038/nnano.2007.187
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