Voltage-dependent ion channels serve as field-effect transistors by opening a gate in response to membrane voltage changes1. The gate's response to voltage is mediated by voltage sensors2, which are arginine-containing structures that must move with respect to the membrane electric field. We have analysed by electron microscopy a voltage-dependent K+ channel from Aeropyrum pernix (KvAP)3. Fab fragments were attached to ‘voltage sensor paddles’ and identified in the electron microscopy map at 10.5 Å resolution. The extracellular surface location of the Fab fragments in the map is consistent with the membrane-depolarized, open conformation of the channel in electrophysiological experiments. Comparison of the map with a crystal structure4 demonstrates that the voltage sensor paddles are ‘up’ (that is, near the channel's extracellular surface) and situated at the protein–lipid interface. This finding supports the hypothesis that in response to changes in voltage the sensors move at the protein–lipid interface5 rather than in a gating pore surrounded by protein6,7.
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Sigworth, F. Voltage gating of ion channels. Q. Rev. Biophys. 27, 1–40 (1994)
Bezanilla, F. The voltage sensor in voltage-dependent ion channels. Physiol. Rev. 80, 555–592 (2000)
Ruta, V., Jiang, Y., Lee, A., Chen, J. & MacKinnon, R. Functional analysis of an archaebacterial voltage-dependent K+ channel. Nature 422, 180–185 (2003)
Jiang, Y. et al. X-ray structure of a voltage-dependent K+ channel. Nature 423, 33–41 (2003)
Jiang, Y., Ruta, V., Chen, J., Lee, A. & MacKinnon, R. The principle of gating charge movement in a voltage-dependent K+ channel. Nature 423, 42–48 (2003)
Bezanilla, F. Voltage sensor movements. J. Gen. Physiol. 120, 465–473 (2002)
Horn, R. Coupled movements in voltage-gated ion channels. J. Gen. Physiol. 120, 449–453 (2002)
Frank, J. Single-particle imaging of macromolecules by cryo-electron microscopy. Annu. Rev. Biophys. Biomol. Struct. 31, 303–319 (2002)
Henderson, R. The potential and limitations of neutrons, electrons and X-rays for atomic resolution microscopy of unstained biological molecules. Q. Rev. Biophys. 28, 171–193 (1995)
Adrian, M., Dubochet, J., Fuller, S. D. & Harris, J. R. Cryo-negative staining. Micron 29, 145–160 (1998)
Golas, M. M., Sander, B., Will, C. L., Luhrmann, R. & Stark, H. Molecular architecture of the multiprotein splicing factor SF3b. Science 300, 980–984 (2003)
Saxton, W. O. & Baumeister, W. The correlation averaging of a regularly arranged bacterial cell envelope protein. J. Microsc. 127, 127–138 (1982)
van Heel, M. Similarity measures between images. Ultramicroscopy 21, 95–100 (1987)
Conway, J. F. et al. Characterization of a conformational epitope on hepatitis B virus core antigen and quasiequivalent variations in antibody binding. J. Virol. 77, 6466–6473 (2003)
Rosenthal, P. B. & Henderson, R. Optimal determination of particle orientation, absolute hand, and contrast loss in single-particle electron cryomicroscopy. J. Mol. Biol. 333, 721–745 (2003)
Laine, M. et al. Atomic proximity between S4 segment and pore domain in Shaker potassium channels. Neuron 39, 467–481 (2003)
Gandhi, C. S., Clark, E., Loots, E., Pralle, A. & Isacoff, E. Y. The orientation and molecular movement of a K+ channel voltage-sensing domain. Neuron 40, 515–525 (2003)
Neale, E. J., Elliott, D. J., Hunter, M. & Sivaprasadarao, A. Evidence for intersubunit interactions between S4 and S5 transmembrane segments of the Shaker potassium channel. J. Biol. Chem. 278, 29079–29085 (2003)
Chandy, K. G. & Gutman, G. A. in Ligand and Voltage-Gated Channels (ed. North, R. A.) 1–72 (CRC, Boca Raton, 1995)
Seoh, S. A., Sigg, D., Papazian, D. M. & Bezanilla, F. Voltage-sensing residues in the S2 and S4 segments of the Shaker K+ channel. Neuron 16, 1159–1167 (1996)
Aggarwal, S. K. & MacKinnon, R. Contribution of the S4 segment to gating charge in the Shaker K+ channel. Neuron 16, 1169–1177 (1996)
Orlova, E. V. et al. Structure of keyhole limpet hemocyanin type 1 (KLH1) at 15 Å resolution by electron cryomicroscopy and angular reconstitution. J. Mol. Biol. 271, 417–437 (1997)
Gabashvili, I. S. et al. Solution structure of the E. coli 70S ribosome at 11.5 Å resolution. Cell 100, 537–549 (2000)
Ludtke, S. J., Baldwin, P. R. & Chiu, W. EMAN: semiautomated software for high-resolution single-particle reconstructions. J. Struct. Biol. 128, 82–97 (1999)
van Heel, M., Harauz, G., Orlova, E. V., Schmidt, R. & Schatz, M. A new generation of the IMAGIC image processing system. J. Struct. Biol. 116, 17–24 (1996)
van Heel, M. Angular reconstitution: a posteriori assignment of projection directions for 3D reconstruction. Ultramicroscopy 21, 111–123 (1987)
Frank, J. et al. SPIDER and WEB: processing and visualization of images in 3D electron microscopy and related fields. J. Struct. Biol. 116, 190–199 (1996)
Sander, B., Golas, M. M. & Stark, H. Automatic CTF correction for single particles based upon multivariate statistical analysis of individual power spectra. J. Struct. Biol. 142, 392–401 (2003)
Hawkes, P. W. in Computer Processing of Electron Microscopic Images (ed. Hawkes, P. W.) 1–33 (Springer, Berlin, 1980)
Jones, T. A., Zou, J. Y., Cowan, S. W. & Kjeldgaard Improved methods for building protein models in electron density maps and the location of errors in these models. Acta Crystallogr. A 47, 110–119 (1991)
We thank members of the MacKinnon lab, S. Darst, N. Opalka and D. Stokes for helpful discussions. This work was supported by grants from the NIH to D.N.W. and R.M. R.M is an investigator in the Howard Hughes Medical Institute.
The authors declare that they have no competing financial interests.
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Jiang, QX., Wang, DN. & MacKinnon, R. Electron microscopic analysis of KvAP voltage-dependent K+ channels in an open conformation. Nature 430, 806–810 (2004). https://doi.org/10.1038/nature02735
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