Achievable resolution from images of biological specimens acquired from a 4k x 4k CCD camera in a 300-kV electron cryomicroscope.
Bacteriorhodopsin and epsilon 15 bacteriophage were used as biological test specimens to evaluate the potential structural resolution with images captured from a 4k x 4k charge-coupled device (CCD) camera in a 300-kV electron cryomicroscope. The phase residuals computed from the bacteriorhodopsin CCD images taken at 84,000x effective magnification averaged 15.7 degrees out to 5.8-A resolution relative to Henderson's published values. Using a single-particle reconstruction technique, we obtained an 8.2-A icosahedral structure of epsilon 15 bacteriophage with the CCD images collected at an effective magnification of 56,000x. These results demonstrate that it is feasible to retrieve biological structures to a resolution close to 2/3 of the Nyquist frequency from the CCD images recorded in a 300-kV electron cryomicroscope at a moderately high but practically acceptable microscope magnification.
National Center for Macromolecular Imaging, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA.
Dong-Hua
DH
Chen
Joanita
J
Jakana
Xiangan
X
Liu
Michael F
MF
Schmid
Wah
W
Chiu
D001435:Bacteriophages / Q000648:ultrastructure; D001436:Bacteriorhodopsins / Q000648:ultrastructure; D020285:Cryoelectron Microscopy / Q000295:instrumentation* / Q000592:standards; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation / Q000592:standards
D001436:Bacteriorhodopsins