羧酶体
羧酶体(英语:carboxysome)是一种细菌微区室,为细菌微区室中被研究最多者[2]。羧酶体为多面体的蛋白结构,外为结构蛋白(BMC-H、BMC-P与BMC-T),内为RuBisCO(固碳酵素)与碳酸酐酶两种酵素[3]。此胞器最早于1956年在蓝菌Phormidium uncinatum中发现[4],后来也在数种其他蓝菌与化学自营细菌(亦进行固碳)中发现,包括盐硫杆状菌、酸硫杆状菌与硝化菌等[3][5][6] 。1973年研究人员首次自Halothiobacillus neapolitanus纯化羧酶体[7]。
羧酶体可能是细菌因应大气中氧气浓度上升演化出的机制,因氧气会与二氧化碳竞争RuBisCO的结合位[8],羧酶体提供了二氧化碳浓度较高的微环境,碳酸酐酶生成二氧化碳后可马上将其供应给RuBisCO进行固碳,避免发生光呼吸的损耗[9][10]。
结构
低温电子显微镜显示羧酶体的形状为正二十面体或接近正二十面体[11][12][13],其外壳为数千个蛋白复合体组成,包裹内部的RuBisCO与碳酸酐酶[11][13]。外壳蛋白大多为组成六聚体的BMC-H,也有少数为组成三聚体的BMC-T与组成五聚体的BMC-P(两者皆为形似六聚体的假六聚体)[14] [15]。BMC-H六聚体中间的孔洞可供固碳作用的受质(碳酸根离子)与产物(3-磷酸甘油酸)经扩散作用进出,此区域带正电的氨基酸可协助扩散进行[14];BMC-P占据正二十面体的顶点[16];BMC-T三聚体中间的孔洞较大且可受调控开关,可使固碳作用较大的受质(RuBP)与产物(3-磷酸甘油酸)进出[17][18]。
种类
羧酶体可分为α与β两型,前者存在α型蓝菌、硝化菌、硫氧化菌与紫细菌中,后者则存在部分蓝菌中[19],两者外观相似,但组成的蛋白种类有异[20][21][22][23],其组成细节、组装机制可能也有差异,经分析外壳蛋白的序列显示两型的羧酶体应是独立演化产生的[23][24]。
α型羧酶体
α型羧酶体又称cso型羧酶体,其中的RuBisCO为IA型,为最早被纯化、研究的细菌微区室[25][26]。此类羧酶体的直径约为100至160奈米[27],BMC-H的种类为CsoS1A、B、C等,BMC-P的种类为CsoS4A、B等,BMC-T的种类则为CsoS1D。
β型羧酶体
β型羧酶体的体积一般大于α型羧酶体,其直径约为200至400奈米[28],其中的RuBisCO为IB型[2]。此类羧酶体中的蛋白由Ccm基因编码,其BMC-H为CcmK、BMC-P为CcmL,BMC-T则为CcmO,其组装为由内至外,即内部的酵素先组装后,再被外部的结构蛋白包裹[29]。
应用
羧酶体为合成生物学研究所关注[30][31][32],已有研究透过基因克隆成功在大肠杆菌中表现α型羧酶体[33],也有生物工程研究透过微调羧酶体外壳蛋白而影响其性质[34]。透过基因克隆将羧酶体转入作物的叶绿体中可能可显著提升其固碳作用的效率而增加产量[35][36],目前已有相关研究进行中[37][38]。
参考文献
- ^ Tsai Y, Sawaya MR, Cannon GC, et al. Structural Analysis of CsoS1A and the Protein Shell of the Halothiobacillus neapolitanus Carboxysome. PLOS Biol. June 2007, 5 (6): e144. PMC 1872035 . PMID 17518518. doi:10.1371/journal.pbio.0050144.
- ^ 2.0 2.1 Kerfeld, Cheryl A.; Erbilgin, Onur. Bacterial microcompartments and the modular construction of microbial metabolism. Trends in Microbiology. 2015, 23 (1): 22–34. ISSN 0966-842X. PMID 25455419. doi:10.1016/j.tim.2014.10.003 .
- ^ 3.0 3.1 Yeates, Todd O.; Kerfeld, Cheryl A.; Heinhorst, Sabine; Cannon, Gordon C.; Shively, Jessup M. Protein-based organelles in bacteria: carboxysomes and related microcompartments. Nature Reviews Microbiology. 2008, 6 (9): 681–691. ISSN 1740-1526. PMID 18679172. S2CID 22666203. doi:10.1038/nrmicro1913.
- ^ G. Drews; W. Niklowitz. Cytology of Cyanophycea. II. Centroplasm and granular inclusions of Phormidium uncinatum. Archiv für Mikrobiologie. 1956, 24 (2): 147–162. PMID 13327992. S2CID 46171409. doi:10.1007/BF00408629.
- ^ E. Gantt; S. F. Conti. Ultrastructure of blue-green algae. Journal of Bacteriology. March 1969, 97 (3): 1486–1493. PMC 249872 . PMID 5776533. doi:10.1128/JB.97.3.1486-1493.1969.
- ^ Shively, J M. Inclusion Bodies of Prokaryotes. Annual Review of Microbiology. 1974, 28 (1): 167–188. ISSN 0066-4227. PMID 4372937. doi:10.1146/annurev.mi.28.100174.001123.
- ^ Shively, J. M.; Ball, F.; Brown, D. H.; Saunders, R. E. Functional Organelles in Prokaryotes: Polyhedral Inclusions (Carboxysomes) of Thiobacillus neapolitanus. Science. 1973, 182 (4112): 584–586. Bibcode:1973Sci...182..584S. ISSN 0036-8075. PMID 4355679. S2CID 10097616. doi:10.1126/science.182.4112.584.
- ^ Badger, M. R. CO
2 concentrating mechanisms in cyanobacteria: molecular components, their diversity and evolution. Journal of Experimental Botany. 2003, 54 (383): 609–622. ISSN 1460-2431. PMID 12554704. doi:10.1093/jxb/erg076 . - ^ Cai, Fei; Menon, Balaraj B.; Cannon, Gordon C.; Curry, Kenneth J.; Shively, Jessup M.; Heinhorst, Sabine. The Pentameric Vertex Proteins Are Necessary for the Icosahedral Carboxysome Shell to Function as a CO
2 Leakage Barrier. PLOS ONE. 2009, 4 (10): e7521. Bibcode:2009PLoSO...4.7521C. ISSN 1932-6203. PMC 2760150 . PMID 19844578. doi:10.1371/journal.pone.0007521 . - ^ Dou, Z.; Heinhorst, S.; Williams, E. B.; Murin, C. D.; Shively, J. M.; Cannon, G. C. CO
2 Fixation Kinetics of Halothiobacillus neapolitanus Mutant Carboxysomes Lacking Carbonic Anhydrase Suggest the Shell Acts as a Diffusional Barrier for CO
2. Journal of Biological Chemistry. 2008, 283 (16): 10377–10384. ISSN 0021-9258. PMID 18258595. doi:10.1074/jbc.M709285200 . - ^ 11.0 11.1 Iancu, Cristina V.; Ding, H. Jane; Morris, Dylan M.; Dias, D. Prabha; Gonzales, Arlene D.; Martino, Anthony; Jensen, Grant J. The Structure of Isolated Synechococcus Strain WH8102 Carboxysomes as Revealed by Electron Cryotomography. Journal of Molecular Biology. 2007, 372 (3): 764–773. ISSN 0022-2836. PMC 2453779 . PMID 17669419. doi:10.1016/j.jmb.2007.06.059.
- ^ Iancu, Cristina V.; Morris, Dylan M.; Dou, Zhicheng; Heinhorst, Sabine; Cannon, Gordon C.; Jensen, Grant J. Organization, Structure, and Assembly of α-Carboxysomes Determined by Electron Cryotomography of Intact Cells. Journal of Molecular Biology. 2010, 396 (1): 105–117. ISSN 0022-2836. PMC 2853366 . PMID 19925807. doi:10.1016/j.jmb.2009.11.019.
- ^ 13.0 13.1 Schmid, Michael F.; Paredes, Angel M.; Khant, Htet A.; Soyer, Ferda; Aldrich, Henry C.; Chiu, Wah; Shively, Jessup M. Structure of Halothiobacillus neapolitanus Carboxysomes by Cryo-electron Tomography. Journal of Molecular Biology. 2006, 364 (3): 526–535. ISSN 0022-2836. PMC 1839851 . PMID 17028023. doi:10.1016/j.jmb.2006.09.024. hdl:11147/2128.
- ^ 14.0 14.1 Kerfeld, C. A. Protein Structures Forming the Shell of Primitive Bacterial Organelles. Science. 2005, 309 (5736): 936–938. Bibcode:2005Sci...309..936K. CiteSeerX 10.1.1.1026.896 . ISSN 0036-8075. PMID 16081736. S2CID 24561197. doi:10.1126/science.1113397.
- ^ Melnicki, Matthew R.; Sutter, Markus; Kerfeld, Cheryl A. Evolutionary relationships among shell proteins of carboxysomes and metabolosomes. Current Opinion in Microbiology. October 2021, 63: 1–9. PMC 8525121 . PMID 34098411. doi:10.1016/j.mib.2021.05.011.
- ^ Tanaka, S.; Kerfeld, C. A.; Sawaya, M. R.; Cai, F.; Heinhorst, S.; Cannon, G. C.; Yeates, T. O. Atomic-Level Models of the Bacterial Carboxysome Shell. Science. 2008, 319 (5866): 1083–1086. Bibcode:2008Sci...319.1083T. ISSN 0036-8075. PMID 18292340. S2CID 5734731. doi:10.1126/science.1151458.
- ^ Cai, F.; Sutter, M.; Cameron, J. C.; Stanley, D. N.; Kinney, J. N.; Kerfeld, C. A. The Structure of CcmP, a Tandem Bacterial Microcompartment Domain Protein from the β-Carboxysome, Forms a Subcompartment Within a Microcompartment. Journal of Biological Chemistry. 2013, 288 (22): 16055–16063. ISSN 0021-9258. PMC 3668761 . PMID 23572529. doi:10.1074/jbc.M113.456897 .
- ^ Klein, Michael G.; Zwart, Peter; Bagby, Sarah C.; Cai, Fei; Chisholm, Sallie W.; Heinhorst, Sabine; Cannon, Gordon C.; Kerfeld, Cheryl A. Identification and Structural Analysis of a Novel Carboxysome Shell Protein with Implications for Metabolite Transport (PDF). Journal of Molecular Biology. 2009, 392 (2): 319–333. ISSN 0022-2836. PMID 19328811. S2CID 42771660. doi:10.1016/j.jmb.2009.03.056. hdl:1721.1/61355 .
- ^ Sommer, Manuel; Cai, Fei; Melnicki, Matthew; Kerfeld, Cheryl A. β-Carboxysome bioinformatics: identification and evolution of new bacterial microcompartment protein gene classes and core locus constraints. Journal of Experimental Botany. 22 June 2017, 68 (14): 3841–3855. PMC 5853843 . PMID 28419380. doi:10.1093/jxb/erx115.
- ^ Zarzycki, J.; Axen, S. D.; Kinney, J. N.; Kerfeld, C. A. Cyanobacterial-based approaches to improving photosynthesis in plants. Journal of Experimental Botany. 2012, 64 (3): 787–798. ISSN 0022-0957. PMID 23095996. doi:10.1093/jxb/ers294 .
- ^ Rae, B. D.; Long, B. M.; Badger, M. R.; Price, G. D. Functions, Compositions, and Evolution of the Two Types of Carboxysomes: Polyhedral Microcompartments That Facilitate CO
2 Fixation in Cyanobacteria and Some Proteobacteria. Microbiology and Molecular Biology Reviews. 2013, 77 (3): 357–379. ISSN 1092-2172. PMC 3811607 . PMID 24006469. doi:10.1128/MMBR.00061-12. - ^ Turmo, Aiko; Gonzalez-Esquer, C. Raul; Kerfeld, Cheryl A. Carboxysomes: metabolic modules for CO
2 fixation. FEMS Microbiology Letters. 2017-08-14, 364 (18). ISSN 1574-6968. PMID 28934381. doi:10.1093/femsle/fnx176. - ^ 23.0 23.1 Kerfeld, Cheryl A; Melnicki, Matthew R. Assembly, function and evolution of cyanobacterial carboxysomes. Current Opinion in Plant Biology. June 2016, 31: 66–75. ISSN 1369-5266. PMID 27060669. doi:10.1016/j.pbi.2016.03.009.
- ^ Melnicki, Matthew R.; Sutter, Markus; Kerfeld, Cheryl A. Evolutionary relationships among shell proteins of carboxysomes and metabolosomes. Current Opinion in Microbiology. October 2021, 63: 1–9. PMC 8525121 . PMID 34098411. doi:10.1016/j.mib.2021.05.011.
- ^ Shively JM, Bock E, Westphal K, Cannon GC. Icosahedral inclusions (carboxysomes) of Nitrobacter agilis. Journal of Bacteriology. November 1977, 132 (2): 673–675. PMC 221910 . PMID 199579. doi:10.1128/JB.132.2.673-675.1977.
- ^ Cannon, G. C.; Shively, J. M. Characterization of a homogenous preparation of carboxysomes from Thiobacillus neapolitanus. Archives of Microbiology. 1983, 134 (1): 52–59. ISSN 0302-8933. S2CID 22329896. doi:10.1007/BF00429407.
- ^ Heinhorst, Sabine; Cannon, Gordon C.; Shively, Jessup M. Carboxysomes and Their Structural Organization in Prokaryotes. Nanomicrobiology. 2014: 75–101. ISBN 978-1-4939-1666-5. doi:10.1007/978-1-4939-1667-2_4.
- ^ Cai, Fei; Dou, Zhicheng; Bernstein, Susan; Leverenz, Ryan; Williams, Eric; Heinhorst, Sabine; Shively, Jessup; Cannon, Gordon; Kerfeld, Cheryl. Advances in Understanding Carboxysome Assembly in Prochlorococcus and Synechococcus Implicate CsoS2 as a Critical Component. Life. 2015, 5 (2): 1141–1171. ISSN 2075-1729. PMC 4499774 . PMID 25826651. doi:10.3390/life5021141 .
- ^ Cameron, Jeffrey?C.; Wilson, Steven?C.; Bernstein, Susan?L.; Kerfeld, Cheryl?A. Biogenesis of a Bacterial Organelle: The Carboxysome Assembly Pathway. Cell. 2013, 155 (5): 1131–1140. ISSN 0092-8674. PMID 24267892. doi:10.1016/j.cell.2013.10.044 .
- ^ Kerfeld, Cheryl A. Plug-and-play for improving primary productivity. American Journal of Botany. December 2015, 102 (12): 1949–1950. ISSN 0002-9122. PMID 26656128. doi:10.3732/ajb.1500409 .
- ^ Zarzycki, Jan; Axen, Seth D.; Kinney, James N.; Kerfeld, Cheryl A. Cyanobacterial-based approaches to improving photosynthesis in plants. Journal of Experimental Botany. 2012-10-23, 64 (3): 787–798. ISSN 1460-2431. PMID 23095996. doi:10.1093/jxb/ers294 .
- ^ Gonzalez-Esquer, C. Raul; Newnham, Sarah E.; Kerfeld, Cheryl A. Bacterial microcompartments as metabolic modules for plant synthetic biology. The Plant Journal. 2016-06-20, 87 (1): 66–75. ISSN 0960-7412. PMID 26991644. doi:10.1111/tpj.13166.
- ^ Bonacci, W.; Teng, P. K.; Afonso, B.; Niederholtmeyer, H.; Grob, P.; Silver, P. A.; Savage, D. F. Modularity of a carbon-fixing protein organelle. Proceedings of the National Academy of Sciences. 2011, 109 (2): 478–483. ISSN 0027-8424. PMC 3258634 . PMID 22184212. doi:10.1073/pnas.1108557109 .
- ^ Cai, Fei; Sutter, Markus; Bernstein, Susan L.; Kinney, James N.; Kerfeld, Cheryl A. Engineering Bacterial Microcompartment Shells: Chimeric Shell Proteins and Chimeric Carboxysome Shells. ACS Synthetic Biology. 2015, 4 (4): 444–453. ISSN 2161-5063. PMID 25117559. doi:10.1021/sb500226j.
- ^ McGrath, JM; Long, SP. Can the cyanobacterial carbon-concentrating mechanism increase photosynthesis in crop species? A theoretical analysis.. Plant Physiology. 2014, 164 (4): 2247–61. PMC 3982776 . PMID 24550242. doi:10.1104/pp.113.232611.
- ^ Yin, X; Struik, PC. Can increased leaf photosynthesis be converted into higher crop mass production? A simulation study for rice using the crop model GECROS.. Journal of Experimental Botany. 2017, 68 (9): 2345–2360. PMC 5447886 . PMID 28379522. doi:10.1093/jxb/erx085.
- ^ Long, BM; Hee, WY. Carboxysome encapsulation of the CO
2-fixing enzyme Rubisco in tobacco chloroplasts.. Nature Communications. 2018, 9 (1): 3570. Bibcode:2018NatCo...9.3570L. PMC 6120970 . PMID 30177711. doi:10.1038/s41467-018-06044-0. - ^ Lin, Myat T.; Occhialini, Alessandro; Andralojc, P. John; Parry, Martin A. J.; Hanson, Maureen R. A faster Rubisco with potential to increase photosynthesis in crops. Nature. 2014, 513 (7519): 547–550. Bibcode:2014Natur.513..547L. ISSN 0028-0836. PMC 4176977 . PMID 25231869. doi:10.1038/nature13776.