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Lipid–protein interactions in double-layered two-dimensional AQP0 crystals

A Corrigendum to this article was published on 11 May 2006

Abstract

Lens-specific aquaporin-0 (AQP0) functions as a specific water pore and forms the thin junctions between fibre cells. Here we describe a 1.9 Å resolution structure of junctional AQP0, determined by electron crystallography of double-layered two-dimensional crystals. Comparison of junctional and non-junctional AQP0 structures shows that junction formation depends on a conformational switch in an extracellular loop, which may result from cleavage of the cytoplasmic amino and carboxy termini. In the centre of the water pathway, the closed pore in junctional AQP0 retains only three water molecules, which are too widely spaced to form hydrogen bonds with each other. Packing interactions between AQP0 tetramers in the crystalline array are mediated by lipid molecules, which assume preferred conformations. We were therefore able to build an atomic model for the lipid bilayer surrounding the AQP0 tetramers, and we describe lipid–protein interactions.

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Figure 1: Electron crystallography of AQP0 junctions.
Figure 2: Structural differences between junctional and non-junctional AQP0.
Figure 3: The water pore in AQP0.
Figure 4: Lipid–protein interactions in double-layered AQP0 2D crystals.

References

  1. Agre, P. et al. Aquaporin water channels—from atomic structure to clinical medicine. J. Physiol. (Lond.) 542, 3–16 (2002)

    CAS  Article  Google Scholar 

  2. Murata, K. et al. Structural determinants of water permeation through aquaporin-1. Nature 407, 599–605 (2000)

    ADS  CAS  Article  Google Scholar 

  3. Fu, D. et al. Structure of a glycerol-conducting channel and the basis for its selectivity. Science 290, 481–486 (2000)

    ADS  CAS  Article  Google Scholar 

  4. Sui, H., Han, B. G., Lee, J. K., Walian, P. & Jap, B. K. Structural basis of water-specific transport through the AQP1 water channel. Nature 414, 872–878 (2001)

    ADS  CAS  Article  Google Scholar 

  5. Ren, G., Reddy, V. S., Cheng, A., Melnyk, P. & Mitra, A. K. Visualization of a water-selective pore by electron crystallography in vitreous ice. Proc. Natl Acad. Sci. USA 98, 1398–1403 (2001)

    ADS  CAS  Article  Google Scholar 

  6. Savage, D. F., Egea, P. F., Robles-Colmenares, Y., O'Connell, J. D. & Stroud, R. M. Architecture and selectivity in aquaporins: 2.5 Å X-ray structure of aquaporin Z. PLoS Biol. 1, E72 (2003)

    Article  Google Scholar 

  7. Gonen, T., Sliz, P., Kistler, J., Cheng, Y. & Walz, T. Aquaporin-0 membrane junctions reveal the structure of a closed water pore. Nature 429, 193–197 (2004)

    ADS  CAS  Article  Google Scholar 

  8. Harries, W. E., Akhavan, D., Miercke, L. J., Khademi, S. & Stroud, R. M. The channel architecture of aquaporin 0 at a 2.2-Å resolution. Proc. Natl Acad. Sci. USA 101, 14045–14050 (2004)

    ADS  CAS  Article  Google Scholar 

  9. de Groot, B. L. & Grubmuller, H. The dynamics and energetics of water permeation and proton exclusion in aquaporins. Curr. Opin. Struct. Biol. 15, 176–183 (2005)

    CAS  Article  Google Scholar 

  10. Kistler, J. & Bullivant, S. Lens gap junctions and orthogonal arrays are unrelated. FEBS Lett. 111, 73–78 (1980)

    CAS  Article  Google Scholar 

  11. Gonen, T., Cheng, Y., Kistler, J. & Walz, T. Aquaporin-0 membrane junctions form upon proteolytic cleavage. J. Mol. Biol. 342, 1337–1345 (2004)

    CAS  Article  Google Scholar 

  12. Nemeth-Cahalan, K. L., Kalman, K. & Hall, J. E. Molecular basis of pH and Ca2+ regulation of aquaporin water permeability. J. Gen. Physiol. 123, 573–580 (2004)

    CAS  Article  Google Scholar 

  13. Gyobu, N. et al. Improved specimen preparation for cryo-electron microscopy using a symmetric carbon sandwich technique. J. Struct. Biol. 146, 325–333 (2004)

    CAS  Article  Google Scholar 

  14. Fujiyoshi, Y. The structural study of membrane proteins by electron crystallography. Adv. Biophys. 35, 25–80 (1998)

    CAS  Article  Google Scholar 

  15. Brunger, A. T. et al. Crystallography & NMR system: a new software suite for macromolecular structure determination. Acta Crystallogr. D Biol. Crystallogr. 54, 905–921 (1998)

    CAS  Article  Google Scholar 

  16. Roy, D., Spector, A. & Farnsworth, P. N. Human lens membrane: comparison of major intrinsic polypeptides from young and old lenses isolated by a new methodology. Exp. Eye Res. 28, 353–358 (1979)

    CAS  Article  Google Scholar 

  17. Takemoto, L., Takehana, M. & Horwitz, J. Covalent changes in MIP26K during aging of the human lens membrane. Invest. Ophthalmol. Vis. Sci. 27, 443–446 (1986)

    CAS  PubMed  Google Scholar 

  18. Laskowski, R. A., MacArthur, M. W., Moss, D. S. & Thornton, J. M. PROCHECK: a program to check the stereochemical qaulity of protein structures. J. Appl. Crystallogr. 26, 283–291 (1993)

    CAS  Article  Google Scholar 

  19. Vriend, G. WHAT IF: a molecular modeling and drug design program. J. Mol. Graph. 8, 526–529 (1990)

    Google Scholar 

  20. Wang, Y., Schulten, K. & Tajkhorshid, E. What makes an aquaporin a glycerol channel? A comparative study of AqpZ and GlpF. Structure 13, 1107–1118 (2005)

    CAS  Article  Google Scholar 

  21. de Groot, B. L. & Grubmuller, H. Water permeation across biological membranes: mechanism and dynamics of aquaporin-1 and GlpF. Science 294, 2353–2357 (2001)

    ADS  CAS  Article  Google Scholar 

  22. Zhu, F., Tajkhorshid, E. & Schulten, K. Molecular dynamics study of aquaporin-1 water channel in a lipid bilayer. FEBS Lett. 504, 212–218 (2001)

    CAS  Article  Google Scholar 

  23. Tajkhorshid, E. et al. Control of the selectivity of the aquaporin water channel family by global orientational tuning. Science 296, 525–530 (2002)

    ADS  CAS  Article  Google Scholar 

  24. Ball, L. E. et al. Water permeability of C-terminally truncated aquaporin 0 (AQP0 1–243) observed in the aging human lens. Invest. Ophthalmol. Vis. Sci. 44, 4820–4828 (2003)

    Article  Google Scholar 

  25. Luecke, H., Schobert, B., Richter, H. T., Cartailler, J. P. & Lanyi, J. K. Structure of bacteriorhodopsin at 1.55 Å resolution. J. Mol. Biol. 291, 899–911 (1999)

    CAS  Article  Google Scholar 

  26. Wiener, M. in Protein–Lipid Interactions: From Membrane Domains to Cellular Networks (ed. Tamm, L. K.) 29–49 (Wiley-VCH, Weinheim, 2005)

    Google Scholar 

  27. Dowhan, W. Molecular basis for membrane phospholipid diversity: why are there so many lipids? Annu. Rev. Biochem. 66, 199–232 (1997)

    CAS  Article  Google Scholar 

  28. Zampighi, G., Simon, S. A., Robertson, J. D., McIntosh, T. J. & Costello, M. J. On the structural organization of isolated bovine lens fiber junctions. J. Cell Biol. 93, 175–189 (1982)

    CAS  Article  Google Scholar 

  29. Kucerka, N. et al. Structure of fully hydrated fluid phase DMPC and DLPC lipid bilayers using X-ray scattering from oriented multilamellar arrays and from unilamellar vesicles. Biophys. J. 88, 2626–2637 (2005)

    ADS  CAS  Article  Google Scholar 

  30. Palsdottir, H. & Hunte, C. Lipids in membrane protein structures. Biochim. Biophys. Acta 1666, 2–18 (2004)

    CAS  Article  Google Scholar 

  31. Schey, K. L., Little, M., Fowler, J. G. & Crouch, R. K. Characterization of human lens major intrinsic protein structure. Invest. Ophthalmol. Vis. Sci. 41, 175–182 (2000)

    CAS  PubMed  Google Scholar 

  32. Ball, L. E., Garland, D. L., Crouch, R. K. & Schey, K. L. Post-translational modifications of aquaporin 0 (AQP0) in the normal human lens: spatial and temporal occurrence. Biochemistry 43, 9856–9865 (2004)

    CAS  Article  Google Scholar 

  33. Shiels, A. & Bassnett, S. Mutations in the founder of the MIP gene family underlie cataract development in the mouse. Nature Genet. 12, 212–215 (1996)

    CAS  Article  Google Scholar 

  34. Shiels, A., Mackay, D., Bassnett, S., Al-Ghoul, K. & Kuszak, J. Disruption of lens fiber cell architecture in mice expressing a chimeric AQP0-LTR protein. FASEB J. 14, 2207–2212 (2000)

    CAS  Article  Google Scholar 

  35. Francis, P. et al. Functional impairment of lens aquaporin in two families with dominantly inherited cataracts. Hum. Mol. Genet. 9, 2329–2334 (2000)

    CAS  Article  Google Scholar 

  36. Francis, P., Berry, V., Bhattacharya, S. & Moore, A. Congenital progressive polymorphic cataract caused by a mutation in the major intrinsic protein of the lens, MIP (AQP0). Br. J. Ophthalmol. 84, 1376–1379 (2000)

    CAS  Article  Google Scholar 

  37. Okamura, T. et al. Bilateral congenital cataracts result from a gain-of-function mutation in the gene for aquaporin-0 in mice. Genomics 81, 361–368 (2003)

    CAS  Article  Google Scholar 

  38. Chepelinsky, A. B. The ocular lens fiber membrane specific protein MIP/aquaporin 0. J. Exp. Zool. A 300, 41–46 (2003)

    Article  Google Scholar 

  39. Lee, A. G. How lipids affect the activities of integral membrane proteins. Biochim. Biophys. Acta 1666, 62–87 (2004)

    CAS  Article  Google Scholar 

  40. Jensen, M. O. & Mouritsen, O. G. Lipids do influence protein function—the hydrophobic matching hypothesis revisited. Biochim. Biophys. Acta 1666, 205–226 (2004)

    CAS  Article  Google Scholar 

  41. Mitsuoka, K. et al. The structure of bacteriorhodopsin at 3.0 Å resolution based on electron crystallography: implication of the charge distribution. J. Mol. Biol. 286, 861–882 (1999)

    CAS  Article  Google Scholar 

  42. Jones, T. A., Zou, J. Y., Cowan, S. W. & Kjeldgaard, M. 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)

    Article  Google Scholar 

Download references

Acknowledgements

This work was supported by NIH funding (to T.W.) and a Grant-in Aid for Specially Promoted Research (to Y.F.).

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Correspondence to Thomas Walz.

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Competing interests

Coordinates and structure factors for junctional and non-junctional AQP0 have been deposited in the Protein Data Bank (accession codes 2B6O and 2B6P, respectively). Reprints and permissions information is available at npg.nature.com/reprintsandpermissions. The authors declare no competing financial interests.

Supplementary information

Supplementary Notes

Lipid-protein and lipid-lipid interactions in the AQP0 junction, together with legends for supplementary figures. (DOC 26 kb)

Supplementary Figure 1

Electron diffraction pattern of a double-layered AQP0 2D crystal tilted to 60°. (PDF 465 kb)

Supplementary Figure 2

Protein packing in 3D and 2D crystals of AQP0. (PDF 226 kb)

Supplementary Figure 3

Residues in loop A of AQP0 involved in junction formation. (PDF 392 kb)

Supplementary Figure 4

The constricted water pore in junctional AQP0. (PDF 653 kb)

Supplementary Figure 5

The water pore in AQP0. (PDF 95 kb)

Supplementary Figure 6

Stereo view of the nine lipids surrounding an AQP0 monomer in the 2D crystals. (PDF 207 kb)

Supplementary Figure 7

Lipids surrounding the AQP0 tetramer mediate the crystal contacts. (PDF 521 kb)

Supplementary Table 1

Crystallographic statistics of non-junctional AQP0 (X-ray). (DOC 20 kb)

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Gonen, T., Cheng, Y., Sliz, P. et al. Lipid–protein interactions in double-layered two-dimensional AQP0 crystals. Nature 438, 633–638 (2005). https://doi.org/10.1038/nature04321

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