ISSN:
1600-5724
Source:
Crystallography Journals Online : IUCR Backfile Archive 1948-2001
Topics:
Chemistry and Pharmacology
,
Geosciences
,
Physics
Notes:
The protein from purple membrane, bacteriorhodopsin, together with lipid, forms two-dimensional membranous arrays of symmetry p3. The protein can also be induced to reform into a planar orthorhombic lattice having at least two slightly different cell dimensions. The p3 and p22121 (small cell) amplitudes have been combined with the known molecular orientation and envelope to show that it is possible to determine phases to the presently known resolution of 6 Å, with the molecular replacement method. This method was then used to extend phases beyond the present 6 Å resolution limit imposed by low-dose imaging, and to obtain a projection showing the structure of purple membrane protein at 3.3 Å resolution. Data from the p3 structure and both orthorhombic forms were used simultaneously for this extension. The procedure suggests a way of extending the resolution of structures based on electron diffraction data from two-dimensional arrays when the transform can be sampled as finely as desired.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1107/S0567739482000047
