Pockets of Short-Range Transient Order and Restricted Topological Heterogeneity in the Guanidine-Denatured State Ensemble of GED of Dynamin†

Biochemistry ◽  
2007 ◽  
Vol 46 (42) ◽  
pp. 11819-11832 ◽  
Author(s):  
Jeetender Chugh ◽  
Shilpy Sharma ◽  
Ramakrishna V. Hosur
2021 ◽  
Vol 119 (1) ◽  
pp. e2109169119
Author(s):  
Kristen A. Gaffney ◽  
Ruiqiong Guo ◽  
Michael D. Bridges ◽  
Shaima Muhammednazaar ◽  
Daoyang Chen ◽  
...  

Defining the denatured state ensemble (DSE) and disordered proteins is essential to understanding folding, chaperone action, degradation, and translocation. As compared with water-soluble proteins, the DSE of membrane proteins is much less characterized. Here, we measure the DSE of the helical membrane protein GlpG of Escherichia coli (E. coli) in native-like lipid bilayers. The DSE was obtained using our steric trapping method, which couples denaturation of doubly biotinylated GlpG to binding of two streptavidin molecules. The helices and loops are probed using limited proteolysis and mass spectrometry, while the dimensions are determined using our paramagnetic biotin derivative and double electron–electron resonance spectroscopy. These data, along with our Upside simulations, identify the DSE as being highly dynamic, involving the topology changes and unfolding of some of the transmembrane (TM) helices. The DSE is expanded relative to the native state but only to 15 to 75% of the fully expanded condition. The degree of expansion depends on the local protein packing and the lipid composition. E. coli’s lipid bilayer promotes the association of TM helices in the DSE and, probably in general, facilitates interhelical interactions. This tendency may be the outcome of a general lipophobic effect of proteins within the cell membranes.


RSC Advances ◽  
2016 ◽  
Vol 6 (98) ◽  
pp. 95584-95589
Author(s):  
Nai-yuan Chang ◽  
Yi-Ci Li ◽  
Cheng-Ping Jheng ◽  
Yu-Ting Kuo ◽  
Cheng-I Lee

The representative structures of the denatured state ensemble of ubiquitin under a native condition and heat-denatured ubiquitin simulated from a fully extended conformation.


2008 ◽  
Vol 469 (1) ◽  
pp. 20-28 ◽  
Author(s):  
Jae-Hyun Cho ◽  
Satoshi Sato ◽  
Jia-Cherng Horng ◽  
Burcu Anil ◽  
Daniel P. Raleigh

2021 ◽  
Author(s):  
Kristen Gaffney ◽  
Ruiqiong Guo ◽  
Michael D Bridges ◽  
Daoyang Chen ◽  
Shaima Muhammednazaar ◽  
...  

Defining the denatured state ensemble (DSE) and intrinsically disordered proteins is essential to understanding protein folding, chaperone action, degradation, translocation and cell signaling. While a majority of studies have focused on water-soluble proteins, the DSE of membrane proteins is much less characterized. Here, we reconstituted the DSE of a helical bundle membrane protein GlpG of Escherichia coli in native lipid bilayers and measured its conformation and compactness. The DSE was obtained using steric trapping, which couples spontaneous denaturation of a doubly biotinylated GlpG to binding of two bulky monovalent streptavidin molecules. Using limited proteolysis and mass spectrometry, we mapped the flexible regions in the DSE. Using our paramagnetic biotin derivative and double electron-electron resonance spectroscopy, we determined the dimensions of the DSE. Finally, we employed our Upside model for molecular dynamics simulations to generate the DSE including the collapsed and fully expanded states in a bilayer. We find that the DSE is highly dynamic involving the topology changes of transmembrane segments and their unfolding. The DSE is expanded relative to the native state, but only to 55-90% of the fully expanded condition. The degree of expansion depends on the chemical potential with regards to local packing and the lipid composition. Our result suggests that the native lipid bilayer promotes the association of helices in the DSE of membrane proteins and, probably in general, facilitating interhelical interactions. This tendency may be the outcome of a general lipophobic effect of proteins within the cell membranes.


2018 ◽  
Vol 27 (12) ◽  
pp. 2062-2072 ◽  
Author(s):  
Abhay K. Thakur ◽  
Wenli Meng ◽  
Lila M. Gierasch

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