PROJECTION STRUCTURE OF THE SURFACE-LAYER OF METHANOPLANUS-LIMICOLA AT 10-ANGSTROM RESOLUTION OBTAINED BY ELECTRON CRYOMICROSCOPY

The projection structure of the surface protein layer of the archaeon Methanoplanus limicola was analysed by electron microscopy and correla tion averaging techniques to a resolution of about 1 nm. For electron microscopy the 2D crystalline protein layer was embedded in aurothiogl ucose. in order to minimize beam damage, specimen drift, charging and other effects degrading the images, cryomicroscopy at -120 degrees C i n combination with spot-scan illumination technique with spot sizes in the range from 200 to 1000 nm was used for recording the images. (C) 1996 Academic Press, Inc.