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-Structure paper
タイトル | It started with a Cys: Spontaneous cysteine modification during cryo-EM grid preparation. |
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ジャーナル・号・ページ | Front Mol Biosci, Vol. 9, Page 945772, Year 2022 |
掲載日 | 2022年8月5日 |
![]() | David P Klebl / Yiheng Wang / Frank Sobott / Rebecca F Thompson / Stephen P Muench / ![]() |
PubMed 要旨 | Advances in single particle cryo-EM data collection and processing have seen a significant rise in its use. However, the influences of the environment generated through grid preparation, by for ...Advances in single particle cryo-EM data collection and processing have seen a significant rise in its use. However, the influences of the environment generated through grid preparation, by for example interactions of proteins with the air-water interface are poorly understood and can be a major hurdle in structure determination by cryo-EM. Initial interactions of proteins with the air-water interface occur quickly and proteins can adopt preferred orientation or partially unfold within hundreds of milliseconds. It has also been shown previously that thin-film layers create hydroxyl radicals. To investigate the potential this might have in cryo-EM sample preparation, we studied two proteins, HSPD1, and beta-galactosidase, and show that cysteine residues are modified in a time-dependent manner. In the case of both HSPD1 and beta-galactosidase, this putative oxidation is linked to partial protein unfolding, as well as more subtle structural changes. We show these modifications can be alleviated through increasing the speed of grid preparation, the addition of DTT, or by sequestering away from the AWI using continuous support films. We speculate that the modification is oxidation by reactive oxygen species which are formed and act at the air-water interface. Finally, we show grid preparation on a millisecond timescale outruns cysteine modification, showing that the reaction timescale is in the range of 100s to 1,000s milliseconds and offering an alternative approach to prevent spontaneous cysteine modification and its consequences during cryo-EM grid preparation. |
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手法 | EM (単粒子) |
解像度 | 2.1 - 6.8 Å |
構造データ | ![]() EMDB-14981: Structure of b-galactosidase without reducing agent prepared by Vitrobot ![]() EMDB-14982: Structure of b-galactosidase with DTT prepared by Vitrobot ![]() EMDB-14983: Structure of b-galactosidase with TCEP prepared by Vitrobot ![]() EMDB-14984: Structure of b-galactosidase on continuous carbon support film prepared by Vitrobot ![]() EMDB-15162: Structure of the human mitochondrial HSPD1 single ring from grids produced in 14ms ![]() EMDB-15167: Structure of the human mitochondrial HSPD1 single ring in the presence of Methionine ![]() EMDB-15176: Structure of the human mitochondrial HSPD1 single ring in the presence of ascorbate ![]() EMDB-15178: Structure of the human mitochondrial HSPD1 single ring (blotted but no DTT) |
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