National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
R35GM142495
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
R00GM121856
引用
ジャーナル: J Biol Chem / 年: 2022 タイトル: A natural fusion of flavodiiron, rubredoxin, and rubredoxin oxidoreductase domains is a self-sufficient water-forming oxidase of Trichomonas vaginalis. 著者: Evana N Abdulaziz / Tristan A Bell / Bazlur Rashid / Mina L Heacock / Tarik Begic / Owen S Skinner / Mohammad A Yaseen / Luke H Chao / Vamsi K Mootha / Antonio J Pierik / Valentin Cracan / 要旨: Microaerophilic pathogens such as Giardia lamblia, Entamoeba histolytica, and Trichomonas vaginalis have robust oxygen consumption systems to detoxify oxygen and maintain intracellular redox balance. ...Microaerophilic pathogens such as Giardia lamblia, Entamoeba histolytica, and Trichomonas vaginalis have robust oxygen consumption systems to detoxify oxygen and maintain intracellular redox balance. This oxygen consumption results from HO-forming NADH oxidase (NOX) activity of two distinct flavin-containing systems: HO-forming NOXes and multicomponent flavodiiron proteins (FDPs). Neither system is membrane bound, and both recycle NADH into oxidized NAD while simultaneously removing O from the local environment. However, little is known about the specific contributions of these systems in T. vaginalis. In this study, we use bioinformatics and biochemical analyses to show that T. vaginalis lacks a NOX-like enzyme and instead harbors three paralogous genes (FDPF1-3), each encoding a natural fusion product between the N-terminal FDP, central rubredoxin (Rb), and C-terminal NADH:Rb oxidoreductase domains. Unlike a "stand-alone" FDP that lacks Rb and oxidoreductase domains, this natural fusion protein with fully populated flavin redox centers directly accepts reducing equivalents of NADH to catalyze the four-electron reduction of oxygen to water within a single polypeptide with an extremely high turnover. Furthermore, using single-particle cryo-EM, we present structural insights into the spatial organization of the FDP core within this multidomain fusion protein. Together, these results contribute to our understanding of systems that allow protozoan parasites to maintain optimal redox balance and survive transient exposure to oxic conditions.
モデル: Quantifoil R1.2/1.3 / 材質: COPPER / メッシュ: 200 / 支持フィルム - 材質: CARBON / 支持フィルム - トポロジー: HOLEY / 支持フィルム - Film thickness: 12 / 前処理 - タイプ: GLOW DISCHARGE / 前処理 - 時間: 30 sec. / 前処理 - 雰囲気: AIR / 前処理 - 気圧: 3.9 kPa 詳細: Grid was washed twice with chloroform and air dried prior to glow discharge and sample application.
凍結
凍結剤: ETHANE / チャンバー内湿度: 100 % / チャンバー内温度: 295 K / 装置: FEI VITROBOT MARK IV / 詳細: Blotting condition: 5 s at +15 blotting force..
詳細
Monodisperse sample
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電子顕微鏡法
顕微鏡
FEI TITAN KRIOS
撮影
フィルム・検出器のモデル: GATAN K3 (6k x 4k) / 撮影したグリッド数: 1 / 実像数: 7398 / 平均電子線量: 54.5 e/Å2 / 詳細: Images were collected as 51-frame movies.
電子線
加速電圧: 300 kV / 電子線源: FIELD EMISSION GUN
電子光学系
照射モード: OTHER / 撮影モード: OTHER / 最大 デフォーカス(公称値): 2.5 µm / 最小 デフォーカス(公称値): 1.3 µm / 倍率(公称値): 105000
実験機器
モデル: Titan Krios / 画像提供: FEI Company
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画像解析
粒子像選択
選択した数: 1511632 詳細: All micrographs were imported into CryoSPARC and preprocessed using the CryoSPARC internal Patch Motion Correction and Patch CTF Estimation jobs. An initial particle set was generated by blob ...詳細: All micrographs were imported into CryoSPARC and preprocessed using the CryoSPARC internal Patch Motion Correction and Patch CTF Estimation jobs. An initial particle set was generated by blob picking particles between 80 and 180 angstroms in diameter from all micrographs. These particles were twice sequentially subjected to 2D classification, and the best classes selected. The micrographs were then manually curated to remove images with minimum CTF fits of 9 angstrom or greater. After curation, 6,938 of the original 7,398 movies remained under consideration. The 2D classes selected from blob picking were used to train a Topaz model, and the model was used to pick particles from the curated micrographs. Duplicate particles were removed by excluding particles with a center within 125 angstrom of another particle.
初期モデル
モデルのタイプ: NONE / 詳細: Model generated ab initio in RELION