| 1. |
|
|
| 2. |
- Gault, Joseph, et al.
(författare)
-
Mass Spectrometry Reveals the Direct Action of a Chemical Chaperone
- 2018
-
Ingår i: The Journal of Physical Chemistry Letters. - : American Chemical Society (ACS). - 1948-7185. ; 9:14, s. 4082-4086
-
Tidskriftsartikel (refereegranskat)abstract
- Despite their fundamental biological importance and therapeutic potential, the interactions between chemical chaperones and proteins remain difficult to capture due to their transient and nonspecific nature. Using a simple mass spectrometric assay, we are able to follow the interactions between proteins and the chemical chaperone trimethylamine-N-oxide (TMAO). In this manner, we directly observe that the counteraction of TMAO and the denaturant urea is driven by the exclusion of TMAO from the protein surface, whereas the surfactant lauryl dimethylamine-N-oxide cannot be displaced. Our results clearly demonstrate a direct chaperoning mechanism for TMAO, corroborating extensive computational studies, and pave the way for the use of nondenaturing mass spectrometry and related techniques to study chemical chaperones in molecular detail.
|
|
| 3. |
- Yen, Hsin-Yung, et al.
(författare)
-
Electrospray ionization of native membrane proteins proceeds via a charge equilibration step
- 2022
-
Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 12:16, s. 9671-9680
-
Tidskriftsartikel (refereegranskat)abstract
- Electrospray ionization mass spectrometry is increasingly applied to study the structures and interactions of membrane protein complexes. However, the charging mechanism is complicated by the presence of detergent micelles during ionization. Here, we show that the final charge of membrane proteins can be predicted by their molecular weight when released from the non-charge reducing saccharide detergents. Our data indicate that PEG detergents lower the charge depending on the number of detergent molecules in the surrounding micelle, whereas fos-choline detergents may additionally participate in ion–ion reactions after desolvation. The supercharging reagent sulfolane, on the other hand, has no discernible effect on the charge of detergent-free membrane proteins. Taking our observations into the context of protein-detergent interactions in the gas phase, we propose a charge equilibration model for the generation of native-like membrane protein ions. During ionization of the protein-detergent complex, the ESI charges are distributed between detergent and protein according to proton affinity of the detergent, number of detergent molecules, and surface area of the protein. Charge equilibration influenced by detergents determines the final charge state of membrane proteins. This process likely contributes to maintaining a native-like fold after detergent release and can be harnessed to stabilize particularly labile membrane protein complexes in the gas phase.
|
|
