Three-dimensional structure of a cell wall glycoprotein |
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Authors: | PJ Shaw GJ Hills |
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Institution: | John Innes Institute Colney Lane, Norwich, NR4 7UH, England |
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Abstract: | Electron microscopy and computer image analysis have been used to determine the three-dimensional structure of the crystalline glycoprotein cell wall layer of the alga Lobomonas piriformis. Images of negatively stained specimens, tilted through a range of angles up to 70 °, were combined to give a map of the molecular envelope to a resolution of 2.0 nm. The cell wall layer consists of crystalline plates the centres and edges of which display distinctly different but isomorphous structures. A comparison of three-dimensional reconstructions of the two areas shows the difference probably to be due to a conformational change of one of the glycoprotein subunits. The structure consists of two sets of dimers composed of rod-shaped subunits which lie with their long axes approximately in the plane of the crystal. The centre-edge transition may have significance in the pathway of accretion of new subunits during cell wall growth. |
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Keywords: | Author to whom all correspondence should be addressed |
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