title: Flopping polypeptide chains and Suleika's subtle imperfections: analysis of variations in the electron micrograph of a purple membrane crystal.
abstract: Patch averaging, a method of data analysis combining correlation averaging with multivariate statistical analysis, was applied to a high-resolution image of a purple membrane thin crystal. The observed variational patterns fall in two categories: non-crystallographic, related to small electron-optical distortions of the microscope, and crystallographic, conceivably related to variations in the locations of flexible segments of the polypeptide chain on the surface of the membrane.
authors: Wadsworth Center for Laboratories and Research, New York State Department of Health, Albany 12201-0509.
authors: J
authors: J
authors: Frank
authors: W
authors: W
authors: Chiu
authors: R
authors: R
authors: Henderson
mesh_terms: D001436:Bacteriorhodopsins / Q000737:chemistry*; D003461:Crystallography; D007091:Image Processing, Computer-Assisted / Q000379:methods* / Q000706:statistics & numerical data; D008854:Microscopy, Electron; D015999:Multivariate Analysis
chemical_list: D001436:Bacteriorhodopsins