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High resolution surface structure of E. coli GroES oligomer by atomic force microscopy
Author(s) -
Mou Jianxun,
Czajkowsky D.M.,
Sheng Sitong Jun,
Ho Rouya,
Shao Zhifeng
Publication year - 1996
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(96)00112-3
Subject(s) - groes , groel , oligomer , crystallography , chemistry , atomic force microscopy , materials science , biophysics , nanotechnology , biology , escherichia coli , polymer chemistry , biochemistry , gene
Using atomic force microscopy (AFM) in aqueous solution, we show that the surface structure of the oligomeric GroES can be obtained up to 10 Å resolution. The seven subunits of the heptamer were well resolved without image averaging. The overall dimension of the GroES heptamer was 8.4±0.4 nm in diameter and 3.0±0.3 nm high. However, the AFM images further suggest that there is a central protrusion of 0.8±0.2 nm high and 4.5±0.4 nm in diameter on one side of GroES which displays a profound seven‐fold symmetry. It was found that GroEL could not bind to the adsorbed GroES in the presence of AMP‐PNP and Mg 2+ , suggesting that the side of GroES with the central protrusion faces away from the GroEL lumen, because only one side of GroES was observed under these conditions. Based on the results from both electron and atomic force microscopy, a surface model for the GroES is proposed.