Identification of a carbonic anhydrase-Rubisco complex within the alpha-carboxysome.
Identification of a carbonic anhydrase-Rubisco complex within the alpha-carboxysome.
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DOI：
10.1073/pnas.2308600120
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发表时间：
2023-10-24
影响因子：
11.1
通讯作者：
Savage, David F.
中科院分区：
文献类型：
--
作者：
Blikstad, Cecilia;Dugan, Eli J.;Laughlin, Thomas G.;Turnsek, Julia B.;Liu, Mira D.;Shoemaker, Sophie R.;Vogiatzi, Nikoleta;Remis, Jonathan P.;Savage, David F.
Rubisco负责地球上大部分的无机碳同化。为了确保有效地固定二氧化碳，蓝藻和许多自养蛋白细菌将二氧化碳浓缩在羧体中，羧体是一种细菌细胞器，将Rubisco和碳酸酐酶包裹在蛋白质壳中。目前尚不清楚这种250多万吨的蛋白质复合体是如何在细胞内高保真地组装的。在这里，我们探索了碳酸酐酶CsoSCA的包埋机制，并证明了它是通过碳酸酐酶-Rubisco复合体被结合到α-羧体中的。我们的结果更新了当前的羧体生物发生模型，并为将二氧化碳浓缩机制工程到作物和工业相关微生物以提高生长和产量的战略提供了信息。羧基体是包裹二氧化碳固定的关键酶--Rubisco和碳酸氢酶--的蛋白质细胞器，是细菌二氧化碳浓缩机制(CCM)的核心。在CCM中，活跃积累的胞质碳酸氢盐扩散到羧体中，并被碳酸酐酶转化为二氧化碳，在Rubisco附近产生高二氧化碳浓度，并确保有效的羧化作用。α-羧体的自组装是由固有的无序支架蛋白CsoS2协调的，它与Rubisco和羧体体壳蛋白相互作用，但尚不清楚碳酸酐酶CsoSCA是如何结合到α-羧体中的。在这里，我们提出了碳酸酐酶包埋α-羧酸体的结构基础。我们发现CsoSCA通过一个内在无序的N-末端结构域与Rubisco直接相互作用。该多肽与Rubisco络合物的1.98ä单颗粒冷冻电子显微镜结构表明，CsoSCA结合主要是由氢键网络介导的。CsoSCA的结合部位与CsoS2的结合部位有重叠，但这两种蛋白质使用的结合基序和结合方式有很大不同，表明Rubisco结合部位具有可塑性。我们的结果促进了对羧体生物发生的理解，并突出了Rubisco的重要性，它不仅作为一种酶，而且作为通过蛋白质相互作用调节组装的中心枢纽。
Rubisco is responsible for the majority of inorganic carbon assimilation on Earth. To ensure efficient CO2 fixation, cyanobacteria and many autotrophic proteobacteria concentrate CO2 in the carboxysome, a bacterial organelle encapsulating Rubisco and carbonic anhydrase within a protein shell. It remains unknown exactly how this 250+ megadalton protein complex assembles with high fidelity inside cells. Here, we explore the encapsulation mechanism of the carbonic anhydrase, CsoSCA, and demonstrate that it is incorporated into the α-carboxysome via a carbonic anhydrase–Rubisco complex. Our results update the current model for carboxysome biogenesis and inform strategies for engineering CO2 concentration mechanisms into crops and industrially relevant microorganisms for improved growth and yields. Carboxysomes are proteinaceous organelles that encapsulate key enzymes of CO2 fixation—Rubisco and carbonic anhydrase—and are the centerpiece of the bacterial CO2 concentrating mechanism (CCM). In the CCM, actively accumulated cytosolic bicarbonate diffuses into the carboxysome and is converted to CO2 by carbonic anhydrase, producing a high CO2 concentration near Rubisco and ensuring efficient carboxylation. Self-assembly of the α-carboxysome is orchestrated by the intrinsically disordered scaffolding protein, CsoS2, which interacts with both Rubisco and carboxysomal shell proteins, but it is unknown how the carbonic anhydrase, CsoSCA, is incorporated into the α-carboxysome. Here, we present the structural basis of carbonic anhydrase encapsulation into α-carboxysomes from Halothiobacillus neapolitanus. We find that CsoSCA interacts directly with Rubisco via an intrinsically disordered N-terminal domain. A 1.98 Å single-particle cryoelectron microscopy structure of Rubisco in complex with this peptide reveals that CsoSCA binding is predominantly mediated by a network of hydrogen bonds. CsoSCA's binding site overlaps with that of CsoS2, but the two proteins utilize substantially different motifs and modes of binding, revealing a plasticity of the Rubisco binding site. Our results advance the understanding of carboxysome biogenesis and highlight the importance of Rubisco, not only as an enzyme but also as a central hub for mediating assembly through protein interactions.
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DOI：
10.3390/life5021141
发表时间：
2015-03-27
期刊：
Life (Basel, Switzerland)
影响因子：
--
作者：
Cai F;Dou Z;Bernstein SL;Leverenz R;Williams EB;Heinhorst S;Shively J;Cannon GC;Kerfeld CA
通讯作者：
Kerfeld CA
影响因子：
7.7
作者：
Flamholz AI;Dugan E;Blikstad C;Gleizer S;Ben-Nissan R;Amram S;Antonovsky N;Ravishankar S;Noor E;Bar-Even A;Milo R;Savage DF
通讯作者：
Savage DF
影响因子：
14.9
作者：
Bailey TL;Johnson J;Grant CE;Noble WS
通讯作者：
Noble WS
影响因子：
14.9
作者：
Drozdetskiy A;Cole C;Procter J;Barton GJ
通讯作者：
Barton GJ
DOI：
10.1107/s2059798318006551
发表时间：
2018-06-01
期刊：
Acta crystallographica. Section D, Structural biology
影响因子：
--
作者：
Afonine PV;Poon BK;Read RJ;Sobolev OV;Terwilliger TC;Urzhumtsev A;Adams PD
通讯作者：
Adams PD