1
|
Walker RM, Zhang M, Burnap RL. Elucidating the role of primary and secondary sphere Zn 2+ ligands in the cyanobacterial CO 2 uptake complex NDH-1 4: The essentiality of arginine in zinc coordination and catalysis. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2024; 1865:149149. [PMID: 38906312 DOI: 10.1016/j.bbabio.2024.149149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Revised: 06/09/2024] [Accepted: 06/13/2024] [Indexed: 06/23/2024]
Abstract
Inorganic carbon uptake in cyanobacteria is facilitated by an energetically intensive CO2-concentrating mechanism (CCM). Specialized Type-1 NDH complexes function as a part of this mechanism to couple photosynthetic energy generated by redox reactions of the electron transport chain (ETC) to CO2 hydration. This active site of CO2 hydration incorporates an arginine side chain as a Zn ligand, diverging from the typical histidine and/or cysteine residues found in standard CAs. In this study, we focused on mutating three amino acids in the active site of the constitutively expressed NDH-14 CO2 hydration complex in Synechococcus sp. PCC7942: CupB-R91, which acts as a zinc ligand, and CupB-E95 and CupB-H89, both of which closely interact with the arginine ligand. These mutations aimed to explore how they affect the unusual metal ligation by CupB-R91 and potentially influence the unusual catalytic process. The most severe defects in activity among the targeted residues are due to a substitution of CupB-R91 and the ionically interacting E95 since both proved essential for the structural stability of the CupB protein. On the other hand, CupB-H89 mutations show a range of catalytic phenotypes indicating a role of this residue in the catalytic mechanism of CO2-hydration, but no evidence was obtained for aberrant carbonic anhydrase activity that would have indicated uncoupling of the CO2-hydration activity from proton pumping. The results are discussed in terms of possible alternative CO2 hydration mechanisms.
Collapse
Affiliation(s)
- Ross M Walker
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK 74078, USA
| | - Minquan Zhang
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK 74078, USA
| | - Robert L Burnap
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK 74078, USA.
| |
Collapse
|
2
|
Pulsford SB, Outram MA, Förster B, Rhodes T, Williams SJ, Badger MR, Price GD, Jackson CJ, Long BM. Cyanobacterial α-carboxysome carbonic anhydrase is allosterically regulated by the Rubisco substrate RuBP. SCIENCE ADVANCES 2024; 10:eadk7283. [PMID: 38728392 PMCID: PMC11086599 DOI: 10.1126/sciadv.adk7283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 04/08/2024] [Indexed: 05/12/2024]
Abstract
Cyanobacterial CO2 concentrating mechanisms (CCMs) sequester a globally consequential proportion of carbon into the biosphere. Proteinaceous microcompartments, called carboxysomes, play a critical role in CCM function, housing two enzymes to enhance CO2 fixation: carbonic anhydrase (CA) and Rubisco. Despite its importance, our current understanding of the carboxysomal CAs found in α-cyanobacteria, CsoSCA, remains limited, particularly regarding the regulation of its activity. Here, we present a structural and biochemical study of CsoSCA from the cyanobacterium Cyanobium sp. PCC7001. Our results show that the Cyanobium CsoSCA is allosterically activated by the Rubisco substrate ribulose-1,5-bisphosphate and forms a hexameric trimer of dimers. Comprehensive phylogenetic and mutational analyses are consistent with this regulation appearing exclusively in cyanobacterial α-carboxysome CAs. These findings clarify the biologically relevant oligomeric state of α-carboxysomal CAs and advance our understanding of the regulation of photosynthesis in this globally dominant lineage.
Collapse
Affiliation(s)
- Sacha B. Pulsford
- ARC Centre of Excellence in Synthetic Biology, Sydney, NSW, Australia
- Research School of Chemistry, The Australian National University, Canberra, ACT 2601, Australia
| | - Megan A. Outram
- Research School of Biology, The Australian National University, Canberra, ACT 2601, Australia
| | - Britta Förster
- Research School of Biology, The Australian National University, Canberra, ACT 2601, Australia
| | - Timothy Rhodes
- Research School of Biology, The Australian National University, Canberra, ACT 2601, Australia
| | - Simon J. Williams
- Research School of Biology, The Australian National University, Canberra, ACT 2601, Australia
| | - Murray R. Badger
- Research School of Biology, The Australian National University, Canberra, ACT 2601, Australia
| | - G. Dean Price
- Research School of Biology, The Australian National University, Canberra, ACT 2601, Australia
| | - Colin J. Jackson
- ARC Centre of Excellence in Synthetic Biology, Sydney, NSW, Australia
- Research School of Chemistry, The Australian National University, Canberra, ACT 2601, Australia
| | - Benedict M. Long
- ARC Centre of Excellence in Synthetic Biology, Sydney, NSW, Australia
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW 2308, Australia
| |
Collapse
|
3
|
Nguyen ND, Pulsford SB, Förster B, Rottet S, Rourke L, Long BM, Price GD. A carboxysome-based CO 2 concentrating mechanism for C 3 crop chloroplasts: advances and the road ahead. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024; 118:940-952. [PMID: 38321620 DOI: 10.1111/tpj.16667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 01/17/2024] [Accepted: 01/24/2024] [Indexed: 02/08/2024]
Abstract
The introduction of the carboxysome-based CO2 concentrating mechanism (CCM) into crop plants has been modelled to significantly increase crop yields. This projection serves as motivation for pursuing this strategy to contribute to global food security. The successful implementation of this engineering challenge is reliant upon the transfer of a microcompartment that encapsulates cyanobacterial Rubisco, known as the carboxysome, alongside active bicarbonate transporters. To date, significant progress has been achieved with respect to understanding various aspects of the cyanobacterial CCM, and more recently, different components of the carboxysome have been successfully introduced into plant chloroplasts. In this Perspective piece, we summarise recent findings and offer new research avenues that will accelerate research in this field to ultimately and successfully introduce the carboxysome into crop plants for increased crop yields.
Collapse
Affiliation(s)
- Nghiem D Nguyen
- Plant Science Division, Research School of Biology, Australian National University, 134 Linnaeus Way, Acton, Australian Capital Territory, 2601, Australia
| | - Sacha B Pulsford
- Research School of Chemistry, Australian National University, 137 Sullivan's Ck Rd, Acton, Australian Capital Territory, 2601, Australia
| | - Britta Förster
- Plant Science Division, Research School of Biology, Australian National University, 134 Linnaeus Way, Acton, Australian Capital Territory, 2601, Australia
| | - Sarah Rottet
- Plant Science Division, Research School of Biology, Australian National University, 134 Linnaeus Way, Acton, Australian Capital Territory, 2601, Australia
| | - Loraine Rourke
- Plant Science Division, Research School of Biology, Australian National University, 134 Linnaeus Way, Acton, Australian Capital Territory, 2601, Australia
| | - Benedict M Long
- Discipline of Biological Sciences, School of Environmental and Life Sciences, ARC Centre of Excellence in Synthetic Biology, The University of Newcastle, University Drive, Callaghan, New South Wales, 2308, Australia
| | - G Dean Price
- Plant Science Division, Research School of Biology, Australian National University, 134 Linnaeus Way, Acton, Australian Capital Territory, 2601, Australia
| |
Collapse
|
4
|
Weerasooriya HN, Longstreth DJ, DiMario RJ, Rosati VC, Cassel BA, Moroney JV. Carbonic anhydrases in the cell wall and plasma membrane of Arabidopsis thaliana are required for optimal plant growth on low CO 2. Front Mol Biosci 2024; 11:1267046. [PMID: 38455761 PMCID: PMC10917985 DOI: 10.3389/fmolb.2024.1267046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 01/15/2024] [Indexed: 03/09/2024] Open
Abstract
Introduction: Plants have many genes encoding both alpha and beta type carbonic anhydrases. Arabidopsis has eight alpha type and six beta type carbonic anhydrase genes. Individual carbonic anhydrases are localized to specific compartments within the plant cell. In this study, we investigate the roles of αCA2 and βCA4.1 in the growth of the plant Arabidopsis thaliana under different CO2 regimes. Methods: Here, we identified the intracellular location of αCA2 and βCA4.1 by linking the coding region of each gene to a fluorescent tag. Tissue expression was determined by investigating GUS expression driven by the αCA2 and βCA4.1 promoters. Finally, the role of these proteins in plant growth and photosynthesis was tested in plants with T-DNA insertions in the αCA2 and βCA4 genes. Results: Fluorescently tagged proteins showed that αCA2 is localized to the cell wall and βCA4.1 to the plasma membrane in plant leaves. Both proteins were expressed in roots and shoots. Plants missing either αCA2 or βCA4 did not show any growth defects under the conditions tested in this study. However, if both αCA2 and βCA4 were disrupted, plants had a significantly smaller above- ground fresh weight and rosette area than Wild Type (WT) plants when grown at 200 μL L-1 CO2 but not at 400 and 1,000 μL L-1 CO2. Growth of the double mutant plants at 200 μL L-1 CO2 was restoredif either αCA2 or βCA4.1 was transformed back into the double mutant plants. Discussion: Both the cell wall and plasma membrane CAs, αCA2 and βCA4.1 had to be knocked down to produce an effect on Arabidopsis growth and only when grown in a CO2 concentration that was significantly below ambient. This indicates that αCA2 and βCA4.1 have overlapping functions since the growth of lines where only one of these CAs was knocked down was indistinguishable from WT growth. The growth results and cellular locations of the two CAs suggest that together, αCA2 and βCA4.1 play an important role in the delivery of CO2 and HCO3 - to the plant cell.
Collapse
Affiliation(s)
| | | | | | | | | | - James V. Moroney
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, United States
| |
Collapse
|
5
|
Oltrogge LM, Chen AW, Chaijarasphong T, Turnšek JB, Savage DF. α-Carboxysome Size Is Controlled by the Disordered Scaffold Protein CsoS2. Biochemistry 2024; 63:219-229. [PMID: 38085650 PMCID: PMC10795168 DOI: 10.1021/acs.biochem.3c00403] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 11/16/2023] [Accepted: 11/17/2023] [Indexed: 01/17/2024]
Abstract
Carboxysomes are protein microcompartments that function in the bacterial CO2 concentrating mechanism (CCM) to facilitate CO2 assimilation. To do so, carboxysomes assemble from thousands of constituent proteins into an icosahedral shell, which encapsulates the enzymes Rubisco and carbonic anhydrase to form structures typically > 100 nm and > 300 megadaltons. Although many of the protein interactions driving the assembly process have been determined, it remains unknown how size and composition are precisely controlled. Here, we show that the size of α-carboxysomes is controlled by the disordered scaffolding protein CsoS2. CsoS2 contains two classes of related peptide repeats that bind to the shell in a distinct fashion, and our data indicate that size is controlled by the relative number of these interactions. We propose an energetic and structural model wherein the two repeat classes bind at the junction of shell hexamers but differ in their preferences for the shell contact angles, and thus the local curvature. In total, this model suggests that a set of specific and repeated interactions between CsoS2 and shell proteins collectively achieve the large size and monodispersity of α-carboxysomes.
Collapse
Affiliation(s)
- Luke M. Oltrogge
- Department
of Molecular and Cell Biology, University
of California, Berkeley, California 94720, United States
- Howard
Hughes Medical Institute, University of California, Berkeley, California 94720, United States
| | - Allen W. Chen
- Department
of Chemistry, University of California, Berkeley, California 94720, United States
| | | | - Julia B. Turnšek
- Department
of Molecular and Cell Biology, University
of California, Berkeley, California 94720, United States
| | - David F. Savage
- Department
of Molecular and Cell Biology, University
of California, Berkeley, California 94720, United States
- Howard
Hughes Medical Institute, University of California, Berkeley, California 94720, United States
- Innovative
Genomics Institute, University of California, Berkeley, California 94720, United States
| |
Collapse
|
6
|
Blikstad C, Dugan EJ, Laughlin TG, Turnšek JB, Liu MD, Shoemaker SR, Vogiatzi N, Remis JP, Savage DF. Identification of a carbonic anhydrase-Rubisco complex within the alpha-carboxysome. Proc Natl Acad Sci U S A 2023; 120:e2308600120. [PMID: 37862384 PMCID: PMC10614612 DOI: 10.1073/pnas.2308600120] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 08/28/2023] [Indexed: 10/22/2023] Open
Abstract
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.
Collapse
Affiliation(s)
- Cecilia Blikstad
- Department of Molecular and Cell Biology, University of California, Berkeley, CA94720
- Department of Chemistry - Ångström Laboratory, Uppsala University, Uppsala75120, Sweden
| | - Eli J. Dugan
- Department of Molecular and Cell Biology, University of California, Berkeley, CA94720
| | - Thomas G. Laughlin
- Department of Molecular and Cell Biology, University of California, Berkeley, CA94720
| | - Julia B. Turnšek
- Department of Molecular and Cell Biology, University of California, Berkeley, CA94720
| | - Mira D. Liu
- Department of Chemistry, University of California, Berkeley, CA94720
| | - Sophie R. Shoemaker
- Department of Molecular and Cell Biology, University of California, Berkeley, CA94720
| | - Nikoleta Vogiatzi
- Department of Chemistry - Ångström Laboratory, Uppsala University, Uppsala75120, Sweden
| | - Jonathan P. Remis
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA94720
| | - David F. Savage
- Department of Molecular and Cell Biology, University of California, Berkeley, CA94720
- HHMI, University of California, Berkeley, CA94720
| |
Collapse
|
7
|
Jiao M, He W, Ouyang Z, Qin Q, Guo Y, Zhang J, Bai Y, Guo X, Yu Q, She J, Hwang PM, Zheng F, Wen Y. Mechanistic and structural insights into the bifunctional enzyme PaaY from Acinetobacter baumannii. Structure 2023; 31:935-947.e4. [PMID: 37329879 DOI: 10.1016/j.str.2023.05.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 03/28/2023] [Accepted: 05/23/2023] [Indexed: 06/19/2023]
Abstract
PaaY is a thioesterase that enables toxic metabolites to be degraded through the bacterial phenylacetic acid (PA) pathway. The Acinetobacter baumannii gene FQU82_01591 encodes PaaY, which we demonstrate to possess γ-carbonic anhydrase activity in addition to thioesterase activity. The crystal structure of AbPaaY in complex with bicarbonate reveals a homotrimer with a canonical γ-carbonic anhydrase active site. Thioesterase activity assays demonstrate a preference for lauroyl-CoA as a substrate. The AbPaaY trimer structure shows a unique domain-swapped C-termini, which increases the stability of the enzyme in vitro and decreases its susceptibility to proteolysis in vivo. The domain-swapped C-termini impact thioesterase substrate specificity and enzyme efficacy without affecting carbonic anhydrase activity. AbPaaY knockout reduced the growth of Acinetobacter in media containing PA, decreased biofilm formation, and impaired hydrogen peroxide resistance. Collectively, AbPaaY is a bifunctional enzyme that plays a key role in the metabolism, growth, and stress response mechanisms of A. baumannii.
Collapse
Affiliation(s)
- Min Jiao
- Center for Microbiome Research of Med-X Institute, Shaanxi Provincial Key Laboratory of Sepsis in Critical Care Medicine, The First Affiliated Hospital, Xi'an Jiaotong University, Xi'an 710061, China
| | - Wenbo He
- Center for Microbiome Research of Med-X Institute, Shaanxi Provincial Key Laboratory of Sepsis in Critical Care Medicine, The First Affiliated Hospital, Xi'an Jiaotong University, Xi'an 710061, China
| | - Zhenlin Ouyang
- Center for Microbiome Research of Med-X Institute, Shaanxi Provincial Key Laboratory of Sepsis in Critical Care Medicine, The First Affiliated Hospital, Xi'an Jiaotong University, Xi'an 710061, China
| | - Qian Qin
- Center for Microbiome Research of Med-X Institute, Shaanxi Provincial Key Laboratory of Sepsis in Critical Care Medicine, The First Affiliated Hospital, Xi'an Jiaotong University, Xi'an 710061, China
| | - Yucheng Guo
- The Key Laboratory of Environment and Genes Related to Disease of Ministry of Education Health Science Center, Xi'an Jiaotong University, Xi'an 710061, China
| | - Jiaxin Zhang
- The Key Laboratory of Environment and Genes Related to Disease of Ministry of Education Health Science Center, Xi'an Jiaotong University, Xi'an 710061, China
| | - Yixin Bai
- Center for Microbiome Research of Med-X Institute, Shaanxi Provincial Key Laboratory of Sepsis in Critical Care Medicine, The First Affiliated Hospital, Xi'an Jiaotong University, Xi'an 710061, China
| | - Xiaolong Guo
- Center for Microbiome Research of Med-X Institute, Shaanxi Provincial Key Laboratory of Sepsis in Critical Care Medicine, The First Affiliated Hospital, Xi'an Jiaotong University, Xi'an 710061, China
| | - Qinyue Yu
- Center for Microbiome Research of Med-X Institute, Shaanxi Provincial Key Laboratory of Sepsis in Critical Care Medicine, The First Affiliated Hospital, Xi'an Jiaotong University, Xi'an 710061, China
| | - Junjun She
- Center for Microbiome Research of Med-X Institute, Shaanxi Provincial Key Laboratory of Sepsis in Critical Care Medicine, The First Affiliated Hospital, Xi'an Jiaotong University, Xi'an 710061, China
| | - Peter M Hwang
- Departments of Medicine and Biochemistry, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB T6G 2R3, Canada
| | - Fang Zheng
- The Key Laboratory of Environment and Genes Related to Disease of Ministry of Education Health Science Center, Xi'an Jiaotong University, Xi'an 710061, China
| | - Yurong Wen
- Center for Microbiome Research of Med-X Institute, Shaanxi Provincial Key Laboratory of Sepsis in Critical Care Medicine, The First Affiliated Hospital, Xi'an Jiaotong University, Xi'an 710061, China; The Key Laboratory of Environment and Genes Related to Disease of Ministry of Education Health Science Center, Xi'an Jiaotong University, Xi'an 710061, China.
| |
Collapse
|
8
|
Kupriyanova EV, Pronina NA, Los DA. Adapting from Low to High: An Update to CO 2-Concentrating Mechanisms of Cyanobacteria and Microalgae. PLANTS (BASEL, SWITZERLAND) 2023; 12:1569. [PMID: 37050194 PMCID: PMC10096703 DOI: 10.3390/plants12071569] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 04/03/2023] [Accepted: 04/04/2023] [Indexed: 06/19/2023]
Abstract
The intracellular accumulation of inorganic carbon (Ci) by microalgae and cyanobacteria under ambient atmospheric CO2 levels was first documented in the 80s of the 20th Century. Hence, a third variety of the CO2-concentrating mechanism (CCM), acting in aquatic photoautotrophs with the C3 photosynthetic pathway, was revealed in addition to the then-known schemes of CCM, functioning in CAM and C4 higher plants. Despite the low affinity of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) of microalgae and cyanobacteria for the CO2 substrate and low CO2/O2 specificity, CCM allows them to perform efficient CO2 fixation in the reductive pentose phosphate (RPP) cycle. CCM is based on the coordinated operation of strategically located carbonic anhydrases and CO2/HCO3- uptake systems. This cooperation enables the intracellular accumulation of HCO3-, which is then employed to generate a high concentration of CO2 molecules in the vicinity of Rubisco's active centers compensating up for the shortcomings of enzyme features. CCM functions as an add-on to the RPP cycle while also acting as an important regulatory link in the interaction of dark and light reactions of photosynthesis. This review summarizes recent advances in the study of CCM molecular and cellular organization in microalgae and cyanobacteria, as well as the fundamental principles of its functioning and regulation.
Collapse
|
9
|
Ang WSL, How JA, How JB, Mueller-Cajar O. The stickers and spacers of Rubiscondensation: assembling the centrepiece of biophysical CO2-concentrating mechanisms. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:612-626. [PMID: 35903998 DOI: 10.1093/jxb/erac321] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 07/21/2022] [Indexed: 06/15/2023]
Abstract
Aquatic autotrophs that fix carbon using ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) frequently expend metabolic energy to pump inorganic carbon towards the enzyme's active site. A central requirement of this strategy is the formation of highly concentrated Rubisco condensates (or Rubiscondensates) known as carboxysomes and pyrenoids, which have convergently evolved multiple times in prokaryotes and eukaryotes, respectively. Recent data indicate that these condensates form by the mechanism of liquid-liquid phase separation. This mechanism requires networks of weak multivalent interactions typically mediated by intrinsically disordered scaffold proteins. Here we comparatively review recent rapid developments that detail the determinants and precise interactions that underlie diverse Rubisco condensates. The burgeoning field of biomolecular condensates has few examples where liquid-liquid phase separation can be linked to clear phenotypic outcomes. When present, Rubisco condensates are essential for photosynthesis and growth, and they are thus emerging as powerful and tractable models to investigate the structure-function relationship of phase separation in biology.
Collapse
Affiliation(s)
- Warren Shou Leong Ang
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551, Singapore
| | - Jian Ann How
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551, Singapore
| | - Jian Boon How
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551, Singapore
| | - Oliver Mueller-Cajar
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551, Singapore
| |
Collapse
|
10
|
Minagawa J, Dann M. Extracellular CahB1 from Sodalinema gerasimenkoae IPPAS B-353 Acts as a Functional Carboxysomal β-Carbonic Anhydrase in Synechocystis sp. PCC6803. PLANTS (BASEL, SWITZERLAND) 2023; 12:265. [PMID: 36678979 PMCID: PMC9865033 DOI: 10.3390/plants12020265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 12/27/2022] [Accepted: 01/03/2023] [Indexed: 06/17/2023]
Abstract
Cyanobacteria mostly rely on the active uptake of hydrated CO2 (i.e., bicarbonate ions) from the surrounding media to fuel their inorganic carbon assimilation. The dehydration of bicarbonate in close vicinity of RuBisCO is achieved through the activity of carboxysomal carbonic anhydrase (CA) enzymes. Simultaneously, many cyanobacterial genomes encode extracellular α- and β-class CAs (EcaA, EcaB) whose exact physiological role remains largely unknown. To date, the CahB1 enzyme of Sodalinema gerasimenkoae (formerly Microcoleus/Coleofasciculus chthonoplastes) remains the sole described active extracellular β-CA in cyanobacteria, but its molecular features strongly suggest it to be a carboxysomal rather than a secreted protein. Upon expression of CahB1 in Synechocystis sp. PCC6803, we found that its expression complemented the loss of endogenous CcaA. Moreover, CahB1 was found to localize to a carboxysome-harboring and CA-active cell fraction. Our data suggest that CahB1 retains all crucial properties of a cellular carboxysomal CA and that the secretion mechanism and/or the machinations of the Sodalinema gerasimenkoae carboxysome are different from those of Synechocystis.
Collapse
Affiliation(s)
- Jun Minagawa
- Division of Environmental Photobiology, National Institute for Basic Biology (NIBB), Aichi, Okazaki 444-8585, Japan
| | - Marcel Dann
- Division of Environmental Photobiology, National Institute for Basic Biology (NIBB), Aichi, Okazaki 444-8585, Japan
- Plant Molecular Biology, Ludwig-Maximilian University (LMU) Munich, 82152 Planegg, Germany
| |
Collapse
|
11
|
Tang J, Zhou H, Jiang Y, Yao D, Waleron KF, Du LM, Daroch M. Characterization of a novel thermophilic cyanobacterium within Trichocoleusaceae, Trichothermofontia sichuanensis gen. et sp. nov., and its CO 2-concentrating mechanism. Front Microbiol 2023; 14:1111809. [PMID: 37180226 PMCID: PMC10172474 DOI: 10.3389/fmicb.2023.1111809] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 04/06/2023] [Indexed: 05/16/2023] Open
Abstract
Thermophiles from extreme thermal environments have shown tremendous potential regarding ecological and biotechnological applications. Nevertheless, thermophilic cyanobacteria remain largely untapped and are rarely characterized. Herein, a polyphasic approach was used to characterize a thermophilic strain, PKUAC-SCTB231 (hereafter B231), isolated from a hot spring (pH 6.62, 55.5°C) in Zhonggu village, China. The analyses of 16S rRNA phylogeny, secondary structures of 16S-23S ITS and morphology strongly supported strain B231 as a novel genus within Trichocoleusaceae. Phylogenomic inference and three genome-based indices further verified the genus delineation. Based on the botanical code, the isolate is herein delineated as Trichothermofontia sichuanensis gen. et sp. nov., a genus closely related to a validly described genus Trichocoleus. In addition, our results suggest that Pinocchia currently classified to belong to the family Leptolyngbyaceae may require revision and assignment to the family Trichocoleusaceae. Furthermore, the complete genome of Trichothermofontia B231 facilitated the elucidation of the genetic basis regarding genes related to its carbon-concentrating mechanism (CCM). The strain belongs to β-cyanobacteria according to its β-carboxysome shell protein and 1B form of Ribulose bisphosphate Carboxylase-Oxygenase (RubisCO). Compared to other thermophilic strains, strain B231contains a relatively low diversity of bicarbonate transporters (only BicA for HCO3- transport) but a higher abundance of different types of carbonic anhydrase (CA), β-CA (ccaA) and γ-CA (ccmM). The BCT1 transporter consistently possessed by freshwater cyanobacteria was absent in strain B231. Similar situation was occasionally observed in freshwater thermal Thermoleptolyngbya and Thermosynechococcus strains. Moreover, strain B231 shows a similar composition of carboxysome shell proteins (ccmK1-4, ccmL, -M, -N, -O, and -P) to mesophilic cyanobacteria, the diversity of which was higher than many thermophilic strains lacking at least one of the four ccmK genes. The genomic distribution of CCM-related genes suggests that the expression of some components is regulated as an operon and others in an independently controlled satellite locus. The current study also offers fundamental information for future taxogenomics, ecogenomics and geogenomic studies on distribution and significance of thermophilic cyanobacteria in the global ecosystem.
Collapse
Affiliation(s)
- Jie Tang
- School of Food and Bioengineering, Chengdu University, Chengdu, Sichuan, China
| | - Huizhen Zhou
- School of Food and Bioengineering, Chengdu University, Chengdu, Sichuan, China
| | - Ying Jiang
- School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Dan Yao
- School of Food and Bioengineering, Chengdu University, Chengdu, Sichuan, China
| | - Krzysztof F. Waleron
- Department of Pharmaceutical Microbiology, Faculty of Pharmacy Medical University of Gdańsk, Gdańsk, Poland
| | - Lian-Ming Du
- School of Food and Bioengineering, Chengdu University, Chengdu, Sichuan, China
| | - Maurycy Daroch
- School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, China
- *Correspondence: Maurycy Daroch,
| |
Collapse
|
12
|
Wang H, Hayer-Hartl M. Phase Separation of Rubisco by the Folded SSUL Domains of CcmM in Beta-Carboxysome Biogenesis. Methods Mol Biol 2023; 2563:269-296. [PMID: 36227479 DOI: 10.1007/978-1-0716-2663-4_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Carboxysomes are large, cytosolic bodies present in all cyanobacteria and many proteobacteria that function as the sites of photosynthetic CO2 fixation by the enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). The carboxysome lumen is enriched with Rubisco and carbonic anhydrase (CA). The polyhedral proteinaceous shell allows the passage of HCO3- ions into the carboxysome, where they are converted to CO2 by CA. Thus, the carboxysome functions as a CO2-concentrating mechanism (CCM), enhancing the efficiency of Rubisco in CO2 fixation. In β-cyanobacteria, carboxysome biogenesis first involves the aggregation of Rubisco by CcmM, a scaffolding protein that exists in two isoforms. Both isoforms contain a minimum of three Rubisco small subunit-like (SSUL) domains, connected by flexible linkers. Multivalent interaction between these linked SSUL domains with Rubisco results in phase separation and condensate formation. Here, we use Rubisco and the short isoform of CcmM (M35) of the β-cyanobacterium Synechococcus elongatus PCC7942 to describe the methods used for in vitro analysis of the mechanism of condensate formation driven by the SSUL domains. The methods include turbidity assays, bright-field and fluorescence microscopy, as well as transmission electron microscopy (TEM) in both negative staining and cryo-conditions.
Collapse
Affiliation(s)
- Huping Wang
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Martinsried, Germany
- Membrane Protein Biosynthesis and Quality Control, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Manajit Hayer-Hartl
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Martinsried, Germany.
| |
Collapse
|
13
|
Abstract
Despite the importance of microcompartments in prokaryotic biology and bioengineering, structural heterogeneity has prevented a complete understanding of their architecture, ultrastructure, and spatial organization. Here, we employ cryo-electron tomography to image α-carboxysomes, a pseudo-icosahedral microcompartment responsible for carbon fixation. We have solved a high-resolution subtomogram average of the Rubisco cargo inside the carboxysome, and determined the arrangement of the enzyme. We find that the H. neapolitanus Rubisco polymerizes in vivo, mediated by the small Rubisco subunit. These fibrils can further pack to form a lattice with six-fold pseudo-symmetry. This arrangement preserves freedom of motion and accessibility around the Rubisco active site and the binding sites for two other carboxysome proteins, CsoSCA (a carbonic anhydrase) and the disordered CsoS2, even at Rubisco concentrations exceeding 800 μM. This characterization of Rubisco cargo inside the α-carboxysome provides insight into the balance between order and disorder in microcompartment organization.
Collapse
|
14
|
Di Fiore A, De Luca V, Langella E, Nocentini A, Buonanno M, Maria Monti S, Supuran CT, Capasso C, De Simone G. Biochemical, structural, and computational studies of a γ-carbonic anhydrase from the pathogenic bacterium Burkholderia pseudomallei. Comput Struct Biotechnol J 2022; 20:4185-4194. [PMID: 36016712 PMCID: PMC9389205 DOI: 10.1016/j.csbj.2022.07.033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 07/18/2022] [Accepted: 07/19/2022] [Indexed: 11/09/2022] Open
Abstract
Melioidosis is a severe disease caused
Burkholderia pseudomallei. γ-carbonic anhydrases (γ-CAs) have been recently
introduced as novel antibacterial drug targets. A new γ-CA from B.
pseudomallei has been investigated by a
multidisciplinary approach. Obtained results provide an important starting point
for developing new anti-melioidosis drugs.
Melioidosis is a severe disease caused by the highly
pathogenic gram-negative bacterium Burkholderia
pseudomallei. Several studies have highlighted the broad
resistance of this pathogen to many antibiotics and pointed out the pivotal
importance of improving the pharmacological arsenal against it. Since γ-carbonic
anhydrases (γ-CAs) have been recently introduced as potential and novel
antibacterial drug targets, in this paper, we report a detailed characterization
of BpsγCA, a γ-CA from B.
pseudomallei by a multidisciplinary approach. In
particular, the enzyme was recombinantly produced and biochemically
characterized. Its catalytic activity at different pH values was measured, the
crystal structure was determined and theoretical pKa calculations were carried
out. Results provided a snapshot of the enzyme active site and dissected the
role of residues involved in the catalytic mechanism and ligand recognition.
These findings are an important starting point for developing new
anti-melioidosis drugs targeting BpsγCA.
Collapse
|
15
|
Getting Closer to Decrypting the Phase Transitions of Bacterial Biomolecules. Biomolecules 2022; 12:biom12070907. [PMID: 35883463 PMCID: PMC9312465 DOI: 10.3390/biom12070907] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 06/24/2022] [Accepted: 06/26/2022] [Indexed: 12/31/2022] Open
Abstract
Liquid–liquid phase separation (LLPS) of biomolecules has emerged as a new paradigm in cell biology, and the process is one proposed mechanism for the formation of membraneless organelles (MLOs). Bacterial cells have only recently drawn strong interest in terms of studies on both liquid-to-liquid and liquid-to-solid phase transitions. It seems that these processes drive the formation of prokaryotic cellular condensates that resemble eukaryotic MLOs. In this review, we present an overview of the key microbial biomolecules that undergo LLPS, as well as the formation and organization of biomacromolecular condensates within the intracellular space. We also discuss the current challenges in investigating bacterial biomacromolecular condensates. Additionally, we highlight a summary of recent knowledge about the participation of bacterial biomolecules in a phase transition and provide some new in silico analyses that can be helpful for further investigations.
Collapse
|
16
|
Carpenter W, Lavania AA, Borden JS, Oltrogge LM, Perez D, Dahlberg PD, Savage DF, Moerner WE. Ratiometric Sensing of Redox Environments Inside Individual Carboxysomes Trapped in Solution. J Phys Chem Lett 2022; 13:4455-4462. [PMID: 35549289 PMCID: PMC9150107 DOI: 10.1021/acs.jpclett.2c00782] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Diffusion of biological nanoparticles in solution impedes our ability to continuously monitor individual particles and measure their physical and chemical properties. To overcome this, we previously developed the interferometric scattering anti-Brownian electrokinetic (ISABEL) trap, which uses scattering to localize a particle and applies electrokinetic forces that counteract Brownian motion, thus enabling extended observation. Here we present an improved ISABEL trap that incorporates a near-infrared scatter illumination beam and rapidly interleaves 405 and 488 nm fluorescence excitation reporter beams. With the ISABEL trap, we monitored the internal redox environment of individual carboxysomes labeled with the ratiometric redox reporter roGFP2. Carboxysomes widely vary in scattering contrast (reporting on size) and redox-dependent ratiometric fluorescence. Furthermore, we used redox sensing to explore the chemical kinetics within intact carboxysomes, where bulk measurements may contain unwanted contributions from aggregates or interfering fluorescent proteins. Overall, we demonstrate the ISABEL trap's ability to sensitively monitor nanoscale biological objects, enabling new experiments on these systems.
Collapse
Affiliation(s)
- William
B. Carpenter
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Abhijit A. Lavania
- Department
of Applied Physics, Stanford University, Stanford, California 94305, United States
| | - Julia S. Borden
- Department
of Molecular and Cell Biology, University
of California Berkeley, Berkeley, California 94720, United States
| | - Luke M. Oltrogge
- Department
of Molecular and Cell Biology, University
of California Berkeley, Berkeley, California 94720, United States
| | - Davis Perez
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Peter D. Dahlberg
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
- Division
of CryoEM and Bioimaging, SSRL, SLAC National
Accelerator Laboratory, Menlo Park, California 94025, United States
| | - David F. Savage
- Department
of Molecular and Cell Biology, University
of California Berkeley, Berkeley, California 94720, United States
| | - W. E. Moerner
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
- Department
of Applied Physics, Stanford University, Stanford, California 94305, United States
| |
Collapse
|
17
|
Tang J, Zhou H, Yao D, Riaz S, You D, Klepacz-Smółka A, Daroch M. Comparative Genomic Analysis Revealed Distinct Molecular Components and Organization of CO 2-Concentrating Mechanism in Thermophilic Cyanobacteria. Front Microbiol 2022; 13:876272. [PMID: 35602029 PMCID: PMC9120777 DOI: 10.3389/fmicb.2022.876272] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 04/04/2022] [Indexed: 12/30/2022] Open
Abstract
Cyanobacteria evolved an inorganic carbon-concentrating mechanism (CCM) to perform effective oxygenic photosynthesis and prevent photorespiratory carbon losses. This process facilitates the acclimation of cyanobacteria to various habitats, particularly in CO2-limited environments. To date, there is limited information on the CCM of thermophilic cyanobacteria whose habitats limit the solubility of inorganic carbon. Here, genome-based approaches were used to identify the molecular components of CCM in 17 well-described thermophilic cyanobacteria. These cyanobacteria were from the genus Leptodesmis, Leptolyngbya, Leptothermofonsia, Thermoleptolyngbya, Thermostichus, and Thermosynechococcus. All the strains belong to β-cyanobacteria based on their β-carboxysome shell proteins with 1B form of Rubisco. The diversity in the Ci uptake systems and carboxysome composition of these thermophiles were analyzed based on their genomic information. For Ci uptake systems, two CO2 uptake systems (NDH-13 and NDH-14) and BicA for HCO3– transport were present in all the thermophilic cyanobacteria, while most strains did not have the Na+/HCO3– Sbt symporter and HCO3– transporter BCT1 were absent in four strains. As for carboxysome, the β-carboxysomal shell protein, ccmK2, was absent only in Thermoleptolyngbya strains, whereas ccmK3/K4 were absent in all Thermostichus and Thermosynechococcus strains. Besides, all Thermostichus and Thermosynechococcus strains lacked carboxysomal β-CA, ccaA, the carbonic anhydrase activity of which may be replaced by ccmM proteins as indicated by comparative domain analysis. The genomic distribution of CCM-related genes was different among the thermophiles, suggesting probably distinct expression regulation. Overall, the comparative genomic analysis revealed distinct molecular components and organization of CCM in thermophilic cyanobacteria. These findings provided insights into the CCM components of thermophilic cyanobacteria and fundamental knowledge for further research regarding photosynthetic improvement and biomass yield of thermophilic cyanobacteria with biotechnological potentials.
Collapse
Affiliation(s)
- Jie Tang
- School of Food and Bioengineering, Chengdu University, Chengdu, China
| | - Huizhen Zhou
- School of Food and Bioengineering, Chengdu University, Chengdu, China
| | - Dan Yao
- School of Food and Bioengineering, Chengdu University, Chengdu, China
| | - Sadaf Riaz
- School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Dawei You
- School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Anna Klepacz-Smółka
- Department of Bioprocess Engineering, Faculty of Process and Environmental Engineering, Łódź University of Technology, Łódź, Poland
| | - Maurycy Daroch
- School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, China
| |
Collapse
|
18
|
Tay JW, Cameron JC. Computational and biochemical methods to measure the activity of carboxysomes and protein organelles in vivo. Methods Enzymol 2022; 683:81-100. [PMID: 37087196 DOI: 10.1016/bs.mie.2022.09.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Cyanobacteria are photosynthetic microorganisms that play important ecological roles as major contributors to global nutrient cycles. Cyanobacteria are highly efficient in carrying out oxygenic photosynthesis because they possess carboxysomes, a class of bacterial microcompartments (BMC) in which a polyhedral protein shell encapsulates the enzymes ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) and carbonic anhydrase and functions as the key component of the cyanobacterial CO2-concentrating mechanism (CCM). Elevated CO2 levels within the carboxysome shell as a result of carbonic anhydrase activity increase the efficiency of RuBisCO. Yet, there remain many questions regarding the flux or exclusion of metabolites across the shell and how the activity of BMCs varies over time. These questions have been difficult to address using traditional ensemble techniques due to the heterogeneity of BMCs extracted from their native hosts or with heterologous expression. In this chapter, we describe a method to film and extract quantitative information about carboxysome activity using molecular biology and live cell, timelapse microscopy. In our method, the production of carboxysomes is first controlled by deleting the native genes required for carboxysome assembly and then re-introducing them under the control of an inducible promoter. This system enables carboxysomes to be tracked through multiple generations of cells and provides a way to quantify the total biomass accumulation attributed to a single carboxysome. While the method presented here was developed specifically for carboxysomes, it could be modified to track and quantify the activity of bacterial microcompartments in general.
Collapse
Affiliation(s)
- Jian Wei Tay
- BioFrontiers Institute, University of Colorado Boulder, Boulder, CO, United States
| | - Jeffrey C Cameron
- Department of Biochemistry, University of Colorado, Boulder, CO, United States; Renewable and Sustainable Energy Institute, University of Colorado, Boulder, CO, United States; National Renewable Energy Laboratory, Golden, CO, United States.
| |
Collapse
|
19
|
Liu LN. Advances in the bacterial organelles for CO 2 fixation. Trends Microbiol 2021; 30:567-580. [PMID: 34802870 DOI: 10.1016/j.tim.2021.10.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 10/19/2021] [Accepted: 10/22/2021] [Indexed: 02/08/2023]
Abstract
Carboxysomes are a family of bacterial microcompartments (BMCs), present in all cyanobacteria and some proteobacteria, which encapsulate the primary CO2-fixing enzyme, Rubisco, within a virus-like polyhedral protein shell. Carboxysomes provide significantly elevated levels of CO2 around Rubisco to maximize carboxylation and reduce wasteful photorespiration, thus functioning as the central CO2-fixation organelles of bacterial CO2-concentration mechanisms. Their intriguing architectural features allow carboxysomes to make a vast contribution to carbon assimilation on a global scale. In this review, we discuss recent research progress that provides new insights into the mechanisms of how carboxysomes are assembled and functionally maintained in bacteria and recent advances in synthetic biology to repurpose the metabolic module in diverse applications.
Collapse
Affiliation(s)
- Lu-Ning Liu
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Crown Street, Liverpool L69 7ZB, UK; College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, 266003 Qingdao, China.
| |
Collapse
|
20
|
Zang K, Wang H, Hartl FU, Hayer-Hartl M. Scaffolding protein CcmM directs multiprotein phase separation in β-carboxysome biogenesis. Nat Struct Mol Biol 2021; 28:909-922. [PMID: 34759380 PMCID: PMC8580825 DOI: 10.1038/s41594-021-00676-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Accepted: 09/28/2021] [Indexed: 12/01/2022]
Abstract
Carboxysomes in cyanobacteria enclose the enzymes Rubisco and carbonic anhydrase to optimize photosynthetic carbon fixation. Understanding carboxysome assembly has implications in agricultural biotechnology. Here we analyzed the role of the scaffolding protein CcmM of the β-cyanobacterium Synechococcus elongatus PCC 7942 in sequestrating the hexadecameric Rubisco and the tetrameric carbonic anhydrase, CcaA. We find that the trimeric CcmM, consisting of γCAL oligomerization domains and linked small subunit-like (SSUL) modules, plays a central role in mediation of pre-carboxysome condensate formation through multivalent, cooperative interactions. The γCAL domains interact with the C-terminal tails of the CcaA subunits and additionally mediate a head-to-head association of CcmM trimers. Interestingly, SSUL modules, besides their known function in recruiting Rubisco, also participate in intermolecular interactions with the γCAL domains, providing further valency for network formation. Our findings reveal the mechanism by which CcmM functions as a central organizer of the pre-carboxysome multiprotein matrix, concentrating the core components Rubisco and CcaA before β-carboxysome shell formation.
Collapse
Affiliation(s)
- Kun Zang
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Huping Wang
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - F Ulrich Hartl
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Manajit Hayer-Hartl
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Martinsried, Germany.
| |
Collapse
|
21
|
Huffine CA, Wheeler LC, Wing B, Cameron JC. Computational modeling and evolutionary implications of biochemical reactions in bacterial microcompartments. Curr Opin Microbiol 2021; 65:15-23. [PMID: 34717259 DOI: 10.1016/j.mib.2021.10.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 10/02/2021] [Indexed: 11/19/2022]
Abstract
Bacterial microcompartments (BMCs) are protein-encapsulated compartments found across at least 23 bacterial phyla. BMCs contain a variety of metabolic processes that share the commonality of toxic or volatile intermediates, oxygen-sensitive enzymes and cofactors, or increased substrate concentration for magnified reaction rates. These compartmentalized reactions have been computationally modeled to explore the encapsulated dynamics, ask evolutionary-based questions, and develop a more systematic understanding required for the engineering of novel BMCs. Many crucial aspects of these systems remain unknown or unmeasured, such as substrate permeabilities across the protein shell, feasibility of pH gradients, and transport rates of associated substrates into the cell. This review explores existing BMC models, dominated in the literature by cyanobacterial carboxysomes, and highlights potentially important areas for exploration.
Collapse
Affiliation(s)
- Clair A Huffine
- BioFrontiers Institute, University of Colorado Boulder, 3415 Colorado Avenue, Boulder, CO 80309, USA; Department of Biochemistry, University of Colorado, Boulder, CO 80309, USA; Renewable and Sustainable Energy Institute, University of Colorado, Boulder, CO 80309, USA; Interdisciplinary Quantitative Biology Program (IQ Biology), BioFrontiers Institute, University of Colorado, Boulder, CO 80309, USA
| | - Lucas C Wheeler
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80309, USA
| | - Boswell Wing
- Department of Geological Sciences, Boulder, CO 80309, USA
| | - Jeffrey C Cameron
- Department of Biochemistry, University of Colorado, Boulder, CO 80309, USA; Renewable and Sustainable Energy Institute, University of Colorado, Boulder, CO 80309, USA; National Renewable Energy Laboratory, Golden, CO 80401, USA.
| |
Collapse
|
22
|
Gamma Carbonic Anhydrases from Hydrothermal Vent Bacteria: Cases of Alternating Active Site Due to a Long Loop with Proton Shuttle Residue. Catalysts 2021. [DOI: 10.3390/catal11101177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Accelerated CO2 sequestration uses carbonic anhydrases (CAs) as catalysts; thus, there is much research on these enzymes. The γ-CA from Escherichia coli (EcoCA-γ) was the first γ-CA to display an active site that switches between “open” and “closed” states through Zn2+ coordination by the proton-shuttling His residue. Here, we explored this occurrence in γ-CAs from hydrothermal vent bacteria and also the γ-CA from Methanosarcina thermophila (Cam) using molecular dynamics. Ten sequences were analyzed through multiple sequence alignment and motif analysis, along with three others from a previous study. Conservation of residues and motifs was high, and phylogeny indicated a close relationship amongst the sequences. All structures, like EcoCA-γ, had a long loop harboring the proton-shuttling residue. Trimeric structures were modeled and simulated for 100 ns at 423 K, with all the structures displaying thermostability. A shift between “open” and “closed” active sites was observed in the 10 models simulated through monitoring the behavior of the His proton-shuttling residue. Cam, which has two Glu proton shuttling residues on long loops (Glu62 and Glu84), also showed an active site switch affected by the first Glu proton shuttle, Glu62. This switch was thus concluded to be common amongst γ-CAs and not an isolated occurrence.
Collapse
|
23
|
Abstract
Bacterial microcompartments (BMCs) confine a diverse array of metabolic reactions within a selectively permeable protein shell, allowing for specialized biochemistry that would be less efficient or altogether impossible without compartmentalization. BMCs play critical roles in carbon fixation, carbon source utilization, and pathogenesis. Despite their prevalence and importance in bacterial metabolism, little is known about BMC “homeostasis,” a term we use here to encompass BMC assembly, composition, size, copy-number, maintenance, turnover, positioning, and ultimately, function in the cell. The carbon-fixing carboxysome is one of the most well-studied BMCs with regard to mechanisms of self-assembly and subcellular organization. In this minireview, we focus on the only known BMC positioning system to date—the maintenance of carboxysome distribution (Mcd) system, which spatially organizes carboxysomes. We describe the two-component McdAB system and its proposed diffusion-ratchet mechanism for carboxysome positioning. We then discuss the prevalence of McdAB systems among carboxysome-containing bacteria and highlight recent evidence suggesting how liquid-liquid phase separation (LLPS) may play critical roles in carboxysome homeostasis. We end with an outline of future work on the carboxysome distribution system and a perspective on how other BMCs may be spatially regulated. We anticipate that a deeper understanding of BMC organization, including nontraditional homeostasis mechanisms involving LLPS and ATP-driven organization, is on the horizon.
Collapse
|
24
|
Sun H, Cui N, Han SJ, Chen ZP, Xia LY, Chen Y, Jiang YL, Zhou CZ. Complex structure reveals CcmM and CcmN form a heterotrimeric adaptor in β-carboxysome. Protein Sci 2021; 30:1566-1576. [PMID: 33928692 DOI: 10.1002/pro.4090] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Revised: 04/14/2021] [Accepted: 04/22/2021] [Indexed: 11/09/2022]
Abstract
Carboxysome is an icosahedral self-assembled microcompartment that sequesters RuBisCO and carbonic anhydrases within a selectively permeable protein shell. The scaffolding proteins, CcmM, and CcmN were proposed to act as adaptors that crosslink the enzymatic core to shell facets. However, the details of interaction pattern remain unknown. Here we obtained a stable heterotrimeric complex of CcmM γ-carbonic anhydrase domain (termed CcmMNT ) and CcmN, with a 1:2 stoichiometry, which interacts with the shell proteins CcmO and CcmL in vitro. The 2.9 Å crystal structure of this heterotrimer revealed an asymmetric bundle composed of one CcmMNT and two CcmN subunits, all of which adopt a triangular left-handed β-helical barrel structure. The central CcmN subunit packs against CcmMNT and another CcmN subunit via a wall-to-edge or wall-to-wall pattern, respectively. Together with previous findings, we propose CcmMNT -CcmN functions as an adaptor to facilitate the recruitment of shell proteins and the assembly of intact β-carboxysome.
Collapse
Affiliation(s)
- Hui Sun
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Ning Cui
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Shu-Jing Han
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Zhi-Peng Chen
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Ling-Yun Xia
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Yuxing Chen
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Yong-Liang Jiang
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Cong-Zhao Zhou
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, China
| |
Collapse
|
25
|
Borden JS, Savage DF. New discoveries expand possibilities for carboxysome engineering. Curr Opin Microbiol 2021; 61:58-66. [PMID: 33798818 DOI: 10.1016/j.mib.2021.03.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 03/06/2021] [Accepted: 03/11/2021] [Indexed: 12/19/2022]
Abstract
Carboxysomes are CO2-fixing protein compartments present in all cyanobacteria and some proteobacteria. These structures are attractive candidates for carbon assimilation bioengineering because they concentrate carbon, allowing the fixation reaction to occur near its maximum rate, and because they self-assemble in diverse organisms with a set of standard biological parts. Recent discoveries have expanded our understanding of how the carboxysome assembles, distributes itself, and sustains its metabolism. These studies have already led to substantial advances in engineering the carboxysome and carbon concentrating mechanism into recombinant organisms, with an eye towards establishing the system in industrial microbes and plants. Future studies may also consider the potential of in vitro carboxysomes for both discovery and applied science.
Collapse
Affiliation(s)
- Julia S Borden
- Department of Molecular & Cellular Biology, UC Berkeley, Berkeley, CA 94720, USA
| | - David F Savage
- Department of Molecular & Cellular Biology, UC Berkeley, Berkeley, CA 94720, USA.
| |
Collapse
|
26
|
In Silico Investigation of Potential Applications of Gamma Carbonic Anhydrases as Catalysts of CO 2 Biomineralization Processes: A Visit to the Thermophilic Bacteria Persephonella hydrogeniphila, Persephonella marina, Thermosulfidibacter takaii, and Thermus thermophilus. Int J Mol Sci 2021; 22:ijms22062861. [PMID: 33799806 PMCID: PMC8000050 DOI: 10.3390/ijms22062861] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 03/02/2021] [Accepted: 03/03/2021] [Indexed: 11/29/2022] Open
Abstract
Carbonic anhydrases (CAs) have been identified as ideal catalysts for CO2 sequestration. Here, we report the sequence and structural analyses as well as the molecular dynamics (MD) simulations of four γ-CAs from thermophilic bacteria. Three of these, Persephonella marina, Persephonella hydrogeniphila, and Thermosulfidibacter takaii originate from hydrothermal vents and one, Thermus thermophilus HB8, from hot springs. Protein sequences were retrieved and aligned with previously characterized γ-CAs, revealing differences in the catalytic pocket residues. Further analysis of the structures following homology modeling revealed a hydrophobic patch in the catalytic pocket, presumed important for CO2 binding. Monitoring of proton shuttling residue His69 (P. marina γ-CA numbering) during MD simulations of P. hydrogeniphila and P. marina’s γ-CAs (γ-PhCA and γ-PmCA), showed a different behavior to that observed in the γ-CA of Escherichia coli, which periodically coordinates Zn2+. This work also involved the search for hotspot residues that contribute to interface stability. Some of these residues were further identified as key in protein communication via betweenness centrality metric of dynamic residue network analysis. T. takaii’s γ-CA showed marginally lower thermostability compared to the other three γ-CA proteins with an increase in conformations visited at high temperatures being observed. Hydrogen bond analysis revealed important interactions, some unique and others common in all γ-CAs, which contribute to interface formation and thermostability. The seemingly thermostable γ-CA from T. thermophilus strangely showed increased unsynchronized residue motions at 423 K. γ-PhCA and γ-PmCA were, however, preliminarily considered suitable as prospective thermostable CO2 sequestration agents.
Collapse
|
27
|
Wang Y, Liu F, Liu M, Shi S, Bi Y, Chen N. Molecular cloning and transcriptional regulation of two γ-carbonic anhydrase genes in the green macroalga Ulva prolifera. Genetica 2021; 149:63-72. [PMID: 33449239 DOI: 10.1007/s10709-020-00112-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2019] [Accepted: 12/06/2020] [Indexed: 12/01/2022]
Abstract
Ulva prolifera O.F. Müller (Ulvophyceae, Chlorophyta) is well known as a typical green-tide forming macroalga which has caused the world's largest macroalgal blooms in the Yellow Sea of China. In this study, two full-length γ-carbonic anhydrase (γ-CA) genes (UpγCA1 and UpγCA2) were cloned from U. prolifera. UpγCA1 has three conserved histidine residues, which act as an active site for binding a zinc metal ion. In UpγCA2, two of the three histidine residues were replaced by serine and arginine, respectively. The two γ-CA genes are clustered together with other γ-CAs in Chlorophyta with strong support value (100% bootstrap) in maximum likelihood (ML) phylogenetic tree. Quantitative real-time PCR (qRT-PCR) analysis showed that stressful environmental conditions markedly inhibited transcription levels of these two γ-CA genes. Low pH value (pH 7.5) significantly increased transcription level of UpγCA2 not UpγCA1 at 12 h, whereas high pH value (pH 8.5) significantly inhibited the transcription of these two γ-CA genes at 6 h. These findings enhanced our understanding on transcriptional regulation of γ-CA genes in response to environmental factors in U. prolifera.
Collapse
Affiliation(s)
- Yu Wang
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao, 266071, Shandong, People's Republic of China
| | - Feng Liu
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao, 266071, Shandong, People's Republic of China. .,Marine Ecology and Environmental Science Laboratory, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, 266237, Shandong, People's Republic of China. .,Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, 266400, Shandong, People's Republic of China.
| | - Manman Liu
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao, 266071, Shandong, People's Republic of China
| | - Shitao Shi
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao, 266071, Shandong, People's Republic of China
| | - Yuping Bi
- Biotechnology Research Center, Shandong Academy of Agricultural Sciences, Jinan, 250100, Shandong, People's Republic of China
| | - Nansheng Chen
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao, 266071, Shandong, People's Republic of China.,Marine Ecology and Environmental Science Laboratory, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, 266237, Shandong, People's Republic of China.,Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, 266400, Shandong, People's Republic of China
| |
Collapse
|
28
|
Koksharova OA, Butenko IO, Pobeguts OV, Safronova NA, Govorun VM. The First Proteomics Study of Nostoc sp. PCC 7120 Exposed to Cyanotoxin BMAA under Nitrogen Starvation. Toxins (Basel) 2020; 12:E310. [PMID: 32397431 PMCID: PMC7290344 DOI: 10.3390/toxins12050310] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 05/05/2020] [Accepted: 05/07/2020] [Indexed: 01/10/2023] Open
Abstract
The oldest prokaryotic photoautotrophic organisms, cyanobacteria, produce many different metabolites. Among them is the water-soluble neurotoxic non-protein amino acid beta-N-methylamino-L-alanine (BMAA), whose biological functions in cyanobacterial metabolism are of fundamental scientific and practical interest. An early BMAA inhibitory effect on nitrogen fixation and heterocyst differentiation was shown in strains of diazotrophic cyanobacteria Nostoc sp. PCC 7120, Nostocpunctiforme PCC 73102 (ATCC 29133), and Nostoc sp. strain 8963 under conditions of nitrogen starvation. Herein, we present a comprehensive proteomic study of Nostoc (also called Anabaena) sp. PCC 7120 in the heterocyst formation stage affecting by BMAA treatment under nitrogen starvation conditions. BMAA disturbs proteins involved in nitrogen and carbon metabolic pathways, which are tightly co-regulated in cyanobacteria cells. The presented evidence shows that exogenous BMAA affects a key nitrogen regulatory protein, PII (GlnB), and some of its protein partners, as well as glutamyl-tRNA synthetase gltX and other proteins that are involved in protein synthesis, heterocyst differentiation, and nitrogen metabolism. By taking into account the important regulatory role of PII, it becomes clear that BMAA has a severe negative impact on the carbon and nitrogen metabolism of starving Nostoc sp. PCC 7120 cells. BMAA disturbs carbon fixation and the carbon dioxide concentrating mechanism, photosynthesis, and amino acid metabolism. Stress response proteins and DNA repair enzymes are upregulated in the presence of BMAA, clearly indicating severe intracellular stress. This is the first proteomic study of the effects of BMAA on diazotrophic starving cyanobacteria cells, allowing a deeper insight into the regulation of the intracellular metabolism of cyanobacteria by this non-protein amino acid.
Collapse
Affiliation(s)
- Olga A. Koksharova
- Lomonosov Moscow State University, Belozersky Institute of Physical-Chemical Biology, Leninskie Gory, 1-40, 119992 Moscow, Russia;
- Institute of Molecular Genetics, Russian Academy of Sciences, Kurchatov Square, 2, 123182 Moscow, Russia
| | - Ivan O. Butenko
- Federal Research and Clinical Centre of Physical-Chemical Medicine, 119435 Moscow, Russia; (I.O.B.); (O.V.P.); (V.M.G.)
| | - Olga V. Pobeguts
- Federal Research and Clinical Centre of Physical-Chemical Medicine, 119435 Moscow, Russia; (I.O.B.); (O.V.P.); (V.M.G.)
| | - Nina A. Safronova
- Lomonosov Moscow State University, Belozersky Institute of Physical-Chemical Biology, Leninskie Gory, 1-40, 119992 Moscow, Russia;
| | - Vadim M. Govorun
- Federal Research and Clinical Centre of Physical-Chemical Medicine, 119435 Moscow, Russia; (I.O.B.); (O.V.P.); (V.M.G.)
| |
Collapse
|
29
|
Vogler M, Karan R, Renn D, Vancea A, Vielberg MT, Grötzinger SW, DasSarma P, DasSarma S, Eppinger J, Groll M, Rueping M. Crystal Structure and Active Site Engineering of a Halophilic γ-Carbonic Anhydrase. Front Microbiol 2020; 11:742. [PMID: 32411108 PMCID: PMC7199487 DOI: 10.3389/fmicb.2020.00742] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 03/30/2020] [Indexed: 11/27/2022] Open
Abstract
Environments previously thought to be uninhabitable offer a tremendous wealth of unexplored microorganisms and enzymes. In this paper, we present the discovery and characterization of a novel γ-carbonic anhydrase (γ-CA) from the polyextreme Red Sea brine pool Discovery Deep (2141 m depth, 44.8°C, 26.2% salt) by single-cell genome sequencing. The extensive analysis of the selected gene helps demonstrate the potential of this culture-independent method. The enzyme was expressed in the bioengineered haloarchaeon Halobacterium sp. NRC-1 and characterized by X-ray crystallography and mutagenesis. The 2.6 Å crystal structure of the protein shows a trimeric arrangement. Within the γ-CA, several possible structural determinants responsible for the enzyme's salt stability could be highlighted. Moreover, the amino acid composition on the protein surface and the intra- and intermolecular interactions within the protein differ significantly from those of its close homologs. To gain further insights into the catalytic residues of the γ-CA enzyme, we created a library of variants around the active site residues and successfully improved the enzyme activity by 17-fold. As several γ-CAs have been reported without measurable activity, this provides further clues as to critical residues. Our study reveals insights into the halophilic γ-CA activity and its unique adaptations. The study of the polyextremophilic carbonic anhydrase provides a basis for outlining insights into strategies for salt adaptation, yielding enzymes with industrially valuable properties, and the underlying mechanisms of protein evolution.
Collapse
Affiliation(s)
- Malvina Vogler
- KAUST Catalysis Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
- Center for Integrated Protein Science Munich, Department of Chemistry, Technische Universität München, Garching, Germany
| | - Ram Karan
- KAUST Catalysis Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Dominik Renn
- KAUST Catalysis Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Alexandra Vancea
- KAUST Catalysis Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Marie-Theres Vielberg
- Center for Integrated Protein Science Munich, Department of Chemistry, Technische Universität München, Garching, Germany
| | - Stefan W. Grötzinger
- KAUST Catalysis Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Priya DasSarma
- Department of Microbiology and Immunology, Institute of Marine and Environmental Technology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Shiladitya DasSarma
- Department of Microbiology and Immunology, Institute of Marine and Environmental Technology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Jörg Eppinger
- KAUST Catalysis Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Michael Groll
- Center for Integrated Protein Science Munich, Department of Chemistry, Technische Universität München, Garching, Germany
| | - Magnus Rueping
- KAUST Catalysis Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| |
Collapse
|
30
|
Momayyezi M, McKown AD, Bell SCS, Guy RD. Emerging roles for carbonic anhydrase in mesophyll conductance and photosynthesis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 101:831-844. [PMID: 31816145 DOI: 10.1111/tpj.14638] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Revised: 11/17/2019] [Accepted: 11/25/2019] [Indexed: 05/24/2023]
Abstract
Carbonic anhydrase (CA) is an abundant protein in most photosynthesizing organisms and higher plants. This review paper considers the physiological importance of the more abundant CA isoforms in photosynthesis, through their effects on CO2 diffusion and other processes in photosynthetic organisms. In plants, CA has multiple isoforms in three different families (α, β and γ) and is mainly known to catalyze the CO2↔HCO3- equilibrium. This reversible conversion has a clear role in photosynthesis, primarily through sustaining the CO2 concentration at the site of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). Despite showing the same major reaction mechanism, the three main CA families are evolutionarily distinct. For different CA isoforms, cellular localization and total gene expression as a function of developmental stage are predicted to determine the role of each family in relation to the net assimilation rate. Reaction-diffusion modeling and observational evidence support a role for CA activity in reducing resistance to CO2 diffusion inside mesophyll cells by facilitating CO2 transfer in both gas and liquid phases. In addition, physical and/or biochemical interactions between CAs and other membrane-bound compartments, for example aquaporins, are suggested to trigger a CO2 -sensing response by stomatal movement. In response to environmental stresses, changes in the expression level of CAs and/or stimulated deactivation of CAs may correspond with lower photosynthetic capacity. We suggest that further studies should focus on the dynamics of the relationship between the activity of CAs (with different subcellular localization, abundance and gene expression) and limitations due to CO2 diffusivity through the mesophyll and supply of CO2 to photosynthetic reactions.
Collapse
Affiliation(s)
- Mina Momayyezi
- Department of Forest and Conservation Sciences, Faculty of Forestry, University of British Columbia, Forest Sciences Centre, 2424 Main Mall, Vancouver, BC, V6T 1Z4, Canada
- Department of Viticulture and Enology, University of California, Davis, CA, 95616, USA
| | - Athena D McKown
- Department of Forest and Conservation Sciences, Faculty of Forestry, University of British Columbia, Forest Sciences Centre, 2424 Main Mall, Vancouver, BC, V6T 1Z4, Canada
| | - Shannon C S Bell
- Department of Forest and Conservation Sciences, Faculty of Forestry, University of British Columbia, Forest Sciences Centre, 2424 Main Mall, Vancouver, BC, V6T 1Z4, Canada
| | - Robert D Guy
- Department of Forest and Conservation Sciences, Faculty of Forestry, University of British Columbia, Forest Sciences Centre, 2424 Main Mall, Vancouver, BC, V6T 1Z4, Canada
| |
Collapse
|
31
|
Structure-activity relationship of human carbonic anhydrase-II inhibitors: Detailed insight for future development as anti-glaucoma agents. Bioorg Chem 2020; 95:103557. [DOI: 10.1016/j.bioorg.2019.103557] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 12/23/2019] [Accepted: 12/24/2019] [Indexed: 01/01/2023]
|
32
|
Wang W, Zhang Y, Wang L, Jing Q, Wang X, Xi X, Zhao X, Wang H. Molecular structure of thermostable and zinc-ion-binding γ-class carbonic anhydrases. Biometals 2019; 32:317-328. [PMID: 30895492 DOI: 10.1007/s10534-019-00190-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 03/18/2019] [Indexed: 12/18/2022]
Abstract
The γ-class carbonic anhydrases (γ-CAs) mainly come from methanogens methane-producing bacteria that grow in hot springs and catalyze the interconversion of carbon dioxide and water to bicarbonate and protons. Here, the γ-CA from Thermus thermophilus HB8 (γ-TtCA) was expressed and purified, its crystal structure was determined at 2.3 Å resolution in space group P1. The asymmetric unit contains two trimers and six catalytic Zn2+. In general, the fold of the protein is similar to those of homologous enzymes from Geobacillus Kaustophilus, Bacillus Cereus, Methanosarcina Thermophila and others. Each monomer comprises a triangular prism-like structure consisting of a left-handed β-helix and a C-terminal α-helix. The catalytic Zn2+ bound to three histidines and a phosphate radical in a tetrahedral fashion. It is located at the interface between the two monomers. Inductively coupled plasma mass spectrometry measurements further suggest that the molar ratio of zinc ions and protein molecules is 1:1. The structure revealed a novel different region situated between the left-handed β-helix and the C-terminal α-helix. Compared to previously reported structures, half of the C-terminal α-helix was replaced with a long loop in this structure. The purified γ-TtCA exhibits no significant carbonic anhydrase activity compared to α-class carbonic anhydrases. This study provides insight into the structural diversity of γ-CAs with potential function for γ-CAs.
Collapse
Affiliation(s)
- Wenming Wang
- Key Laboratory of Chemical Biology and Molecular Engineering of Education Ministry, Institute of Molecular Science, Shanxi University, Taiyuan, 030006, China.
| | - Yao Zhang
- Key Laboratory of Chemical Biology and Molecular Engineering of Education Ministry, Institute of Molecular Science, Shanxi University, Taiyuan, 030006, China
| | - Lele Wang
- Key Laboratory of Chemical Biology and Molecular Engineering of Education Ministry, Institute of Molecular Science, Shanxi University, Taiyuan, 030006, China
| | - Qi Jing
- Key Laboratory of Chemical Biology and Molecular Engineering of Education Ministry, Institute of Molecular Science, Shanxi University, Taiyuan, 030006, China
| | - Xiaolu Wang
- Key Laboratory of Chemical Biology and Molecular Engineering of Education Ministry, Institute of Molecular Science, Shanxi University, Taiyuan, 030006, China
| | - Xiaoli Xi
- Key Laboratory of Chemical Biology and Molecular Engineering of Education Ministry, Institute of Molecular Science, Shanxi University, Taiyuan, 030006, China
| | - Xuan Zhao
- Department of Chemistry, University of Memphis, Memphis, TN, 38152, USA
| | - Hongfei Wang
- Key Laboratory of Chemical Biology and Molecular Engineering of Education Ministry, Institute of Molecular Science, Shanxi University, Taiyuan, 030006, China.
| |
Collapse
|
33
|
Rubisco condensate formation by CcmM in β-carboxysome biogenesis. Nature 2019; 566:131-135. [PMID: 30675061 DOI: 10.1038/s41586-019-0880-5] [Citation(s) in RCA: 126] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2018] [Accepted: 12/14/2018] [Indexed: 01/08/2023]
Abstract
Cells use compartmentalization of enzymes as a strategy to regulate metabolic pathways and increase their efficiency1. The α- and β-carboxysomes of cyanobacteria contain ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco)-a complex of eight large (RbcL) and eight small (RbcS) subunits-and carbonic anhydrase2-4. As HCO3- can diffuse through the proteinaceous carboxysome shell but CO2 cannot5, carbonic anhydrase generates high concentrations of CO2 for carbon fixation by Rubisco6. The shell also prevents access to reducing agents, generating an oxidizing environment7-9. The formation of β-carboxysomes involves the aggregation of Rubisco by the protein CcmM10, which exists in two forms: full-length CcmM (M58 in Synechococcus elongatus PCC7942), which contains a carbonic anhydrase-like domain8 followed by three Rubisco small subunit-like (SSUL) modules connected by flexible linkers; and M35, which lacks the carbonic anhydrase-like domain11. It has long been speculated that the SSUL modules interact with Rubisco by replacing RbcS2-4. Here we have reconstituted the Rubisco-CcmM complex and solved its structure. Contrary to expectation, the SSUL modules do not replace RbcS, but bind close to the equatorial region of Rubisco between RbcL dimers, linking Rubisco molecules and inducing phase separation into a liquid-like matrix. Disulfide bond formation in SSUL increases the network flexibility and is required for carboxysome function in vivo. Notably, the formation of the liquid-like condensate of Rubisco is mediated by dynamic interactions with the SSUL domains, rather than by low-complexity sequences, which typically mediate liquid-liquid phase separation in eukaryotes12,13. Indeed, within the pyrenoids of eukaryotic algae, the functional homologues of carboxysomes, Rubisco adopts a liquid-like state by interacting with the intrinsically disordered protein EPYC114. Understanding carboxysome biogenesis will be important for efforts to engineer CO2-concentrating mechanisms in plants15-19.
Collapse
|
34
|
Huang F, Vasieva O, Sun Y, Faulkner M, Dykes GF, Zhao Z, Liu LN. Roles of RbcX in Carboxysome Biosynthesis in the Cyanobacterium Synechococcus elongatus PCC7942. PLANT PHYSIOLOGY 2019; 179:184-194. [PMID: 30389782 PMCID: PMC6324234 DOI: 10.1104/pp.18.01217] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 10/23/2018] [Indexed: 05/19/2023]
Abstract
Rubisco is the essential enzyme mediating the fixation of atmospheric CO2 during photosynthesis. In cyanobacteria, Rubisco enzymes are densely packed and encapsulated in a specialized organelle known as the carboxysome. Well-defined Rubisco assembly and carboxysome formation are pivotal for efficient CO2 fixation. Numerous chaperone proteins, including RbcX, are essential for proper protein folding and Rubisco assembly. In this study, we investigated the in vivo function of RbcX in the cyanobacterium Synechococcus elongatus PCC 7942 (Syn7942) using molecular, biochemical, and live-cell fluorescence imaging approaches. Our results show that genetic deletion of the rbcX gene affects Rubisco abundance, as well as carboxysome formation and spatial distribution. Moreover, RbcX appears as one component of the carboxysome and shows a dynamic interaction with Rubisco enzymes. These in vivo observations provide insight into the role of RbcX from Syn7942 in mediating carboxysome assembly. Understanding the molecular mechanism underlying Rubisco assembly and carboxysome biogenesis will provide essential information required for engineering functional CO2-fixing complexes in heterogeneous organisms, especially plants, with the aim of boosting photosynthesis and agricultural productivity.
Collapse
Affiliation(s)
- Fang Huang
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom
| | - Olga Vasieva
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom
| | - Yaqi Sun
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom
| | - Matthew Faulkner
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom
| | - Gregory F Dykes
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom
| | - Ziyu Zhao
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom
| | - Lu-Ning Liu
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom
| |
Collapse
|
35
|
Ryan P, Forrester TJB, Wroblewski C, Kenney TMG, Kitova EN, Klassen JS, Kimber MS. The small RbcS-like domains of the β-carboxysome structural protein CcmM bind RubisCO at a site distinct from that binding the RbcS subunit. J Biol Chem 2018; 294:2593-2603. [PMID: 30591587 DOI: 10.1074/jbc.ra118.006330] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 12/13/2018] [Indexed: 12/26/2022] Open
Abstract
Carboxysomes are compartments in bacterial cells that promote efficient carbon fixation by sequestering RubisCO and carbonic anhydrase within a protein shell that impedes CO2 escape. The key to assembling this protein complex is CcmM, a multidomain protein whose C-terminal region is required for RubisCO recruitment. This CcmM region is built as a series of copies (generally 3-5) of a small domain, CcmMS, joined by unstructured linkers. CcmMS domains have weak, but significant, sequence identity to RubisCO's small subunit, RbcS, suggesting that CcmM binds RubisCO by displacing RbcS. We report here the 1.35-Å structure of the first Thermosynechococcus elongatus CcmMS domain, revealing that it adopts a compact, well-defined structure that resembles that of RbcS. CcmMS, however, lacked key RbcS RubisCO-binding determinants, most notably an extended N-terminal loop. Nevertheless, individual CcmMS domains are able to bind RubisCO in vitro with 1.16 μm affinity. Two or four linked CcmMS domains did not exhibit dramatic increases in this affinity, implying that short, disordered linkers may frustrate successive CcmMS domains attempting to simultaneously bind a single RubisCO oligomer. Size-exclusion chromatography-coupled right-angled light scattering (SEC-RALS) and native MS experiments indicated that multiple CcmMS domains can bind a single RubisCO holoenzyme and, moreover, that RbcS is not released from these complexes. CcmMS bound equally tightly to a RubisCO variant in which the α/β domain of RbcS was deleted, suggesting that CcmMS binds RubisCO independently of its RbcS subunit. We propose that, instead, the electropositive CcmMS may bind to an extended electronegative pocket between RbcL dimers.
Collapse
Affiliation(s)
- Patrick Ryan
- From the Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada and
| | - Taylor J B Forrester
- From the Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada and
| | - Charles Wroblewski
- From the Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada and
| | - Tristan M G Kenney
- From the Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada and
| | - Elena N Kitova
- Alberta Glycomics Centre and Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - John S Klassen
- Alberta Glycomics Centre and Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Matthew S Kimber
- From the Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada and
| |
Collapse
|
36
|
Noreña-Caro D, Benton MG. Cyanobacteria as photoautotrophic biofactories of high-value chemicals. J CO2 UTIL 2018. [DOI: 10.1016/j.jcou.2018.10.008] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
|
37
|
Abstract
Bacterial microcompartments (BMCs) are self-assembling organelles that consist of an enzymatic core that is encapsulated by a selectively permeable protein shell. The potential to form BMCs is widespread and found across the kingdom Bacteria. BMCs have crucial roles in carbon dioxide fixation in autotrophs and the catabolism of organic substrates in heterotrophs. They contribute to the metabolic versatility of bacteria, providing a competitive advantage in specific environmental niches. Although BMCs were first visualized more than 60 years ago, it is mainly in the past decade that progress has been made in understanding their metabolic diversity and the structural basis of their assembly and function. This progress has not only heightened our understanding of their role in microbial metabolism but is also beginning to enable their use in a variety of applications in synthetic biology. In this Review, we focus on recent insights into the structure, assembly, diversity and function of BMCs.
Collapse
Affiliation(s)
- Cheryl A. Kerfeld
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Clement Aussignargues
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Jan Zarzycki
- Max-Planck-Institute for Terrestrial Microbiology, D-35043, Marburg, Germany
| | - Fei Cai
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Markus Sutter
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
| |
Collapse
|
38
|
Chaijarasphong T, Savage DF. Sequestered: Design and Construction of Synthetic Organelles. Synth Biol (Oxf) 2018. [DOI: 10.1002/9783527688104.ch14] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Affiliation(s)
- Thawatchai Chaijarasphong
- Mahidol University; Faculty of Science, Department of Biotechnology; Rama VI Rd. Bangkok 10400 Thailand
| | - David F. Savage
- University of California; Department of Molecular and Cell Biology; 2151 Berkeley Way, Berkeley CA 94720 USA
- University of California; Department of Chemistry; 2151 Berkeley Way, Berkeley CA 94720 USA
| |
Collapse
|
39
|
Aspatwar A, Haapanen S, Parkkila S. An Update on the Metabolic Roles of Carbonic Anhydrases in the Model Alga Chlamydomonas reinhardtii. Metabolites 2018. [PMID: 29534024 PMCID: PMC5876011 DOI: 10.3390/metabo8010022] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Carbonic anhydrases (CAs) are metalloenzymes that are omnipresent in nature. CAs catalyze the basic reaction of the reversible hydration of CO2 to HCO3− and H+ in all living organisms. Photosynthetic organisms contain six evolutionarily different classes of CAs, which are namely: α-CAs, β-CAs, γ-CAs, δ-CAs, ζ-CAs, and θ-CAs. Many of the photosynthetic organisms contain multiple isoforms of each CA family. The model alga Chlamydomonas reinhardtii contains 15 CAs belonging to three different CA gene families. Of these 15 CAs, three belong to the α-CA gene family; nine belong to the β-CA gene family; and three belong to the γ-CA gene family. The multiple copies of the CAs in each gene family may be due to gene duplications within the particular CA gene family. The CAs of Chlamydomonas reinhardtii are localized in different subcellular compartments of this unicellular alga. The presence of a large number of CAs and their diverse subcellular localization within a single cell suggests the importance of these enzymes in the metabolic and biochemical roles they perform in this unicellular alga. In the present review, we update the information on the molecular biology of all 15 CAs and their metabolic and biochemical roles in Chlamydomonas reinhardtii. We also present a hypothetical model showing the known functions of CAs and predicting the functions of CAs for which precise metabolic roles are yet to be discovered.
Collapse
Affiliation(s)
- Ashok Aspatwar
- Faculty of Medicine and Life Sciences, University of Tampere, FI-33014 Tampere, Finland.
| | - Susanna Haapanen
- Faculty of Medicine and Life Sciences, University of Tampere, FI-33014 Tampere, Finland.
| | - Seppo Parkkila
- Faculty of Medicine and Life Sciences, University of Tampere, FI-33014 Tampere, Finland.
- Fimlab, Ltd., and Tampere University Hospital, FI-33520 Tampere, Finland.
| |
Collapse
|
40
|
DiMario RJ, Machingura MC, Waldrop GL, Moroney JV. The many types of carbonic anhydrases in photosynthetic organisms. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2018; 268:11-17. [PMID: 29362079 DOI: 10.1016/j.plantsci.2017.12.002] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 11/22/2017] [Accepted: 12/02/2017] [Indexed: 05/24/2023]
Abstract
Carbonic anhydrases (CAs) are enzymes that catalyze the interconversion of CO2 and HCO3-. In nature, there are multiple families of CA, designated with the Greek letters α through θ. CAs are ubiquitous in plants, algae and photosynthetic bacteria, often playing essential roles in the CO2 concentrating mechanisms (CCMs) which enhance the delivery of CO2 to Rubisco. As algal CCMs become better characterized, it is clear that different types of CAs are playing the same role in different algae. For example, an α-CA catalyzes the conversion of accumulated HCO3- to CO2 in the green alga Chlamydomonas reinhardtii, while a θ-CA performs the same function in the diatom Phaeodactylum tricornutum. In this review we argue that, in addition to its role of delivering CO2 for photosynthesis, other metabolic roles of CA have likely changed as the Earth's atmospheric CO2 level decreased. Since the algal and plant lineages diverged well before the decrease in atmospheric CO2, it is likely that plant, algae and photosynthetic bacteria all adapted independently to the drop in atmospheric CO2. In light of this, we will discuss how the roles of CAs may have changed over time, focusing on the role of CA in pH regulation, how CAs affect CO2 supply for photosynthesis and how CAs may help in the delivery of HCO3- for other metabolic reactions.
Collapse
Affiliation(s)
- Robert J DiMario
- School of Biological Sciences, Molecular Plant Sciences, Washington State University, Pullman, WA 99164, United States.
| | - Marylou C Machingura
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, United States.
| | - Grover L Waldrop
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, United States.
| | - James V Moroney
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, United States.
| |
Collapse
|
41
|
Fang Y, Huang F, Faulkner M, Jiang Q, Dykes GF, Yang M, Liu LN. Engineering and Modulating Functional Cyanobacterial CO 2-Fixing Organelles. FRONTIERS IN PLANT SCIENCE 2018; 9:739. [PMID: 29922315 PMCID: PMC5996877 DOI: 10.3389/fpls.2018.00739] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 05/15/2018] [Indexed: 05/12/2023]
Abstract
Bacterial microcompartments (BMCs) are proteinaceous organelles widespread among bacterial phyla and provide a means for compartmentalizing specific metabolic pathways. They sequester catalytic enzymes from the cytoplasm, using an icosahedral proteinaceous shell with selective permeability to metabolic molecules and substrates, to enhance metabolic efficiency. Carboxysomes were the first BMCs discovered and their unprecedented capacity of CO2 fixation allows cyanobacteria to make a significant contribution to global carbon fixation. There is an increasing interest in utilizing synthetic biology to construct synthetic carboxysomes in new hosts, i.e., higher plants, to enhance carbon fixation and productivity. Here, we report the construction of a synthetic operon of the β-carboxysome from the cyanobacterium Synechococcus elongatus PCC7942 to generate functional β-carboxysome-like structures in Escherichia coli. The protein expression, structure, assembly, and activity of synthetic β-carboxysomes were characterized in depth using confocal, electron and atomic force microscopy, proteomics, immunoblot analysis, and enzymatic assays. Furthermore, we examined the in vivo interchangeability of β-carboxysome building blocks with other BMC components. To our knowledge, this is the first production of functional β-carboxysome-like structures in heterologous organisms. It provides important information for the engineering of fully functional carboxysomes and CO2-fixing modules in higher plants. The study strengthens our synthetic biology toolbox for generating BMC-based organelles with tunable activities and new scaffolding biomaterials for metabolic improvement and molecule delivery.
Collapse
|
42
|
Rohnke BA, Singh SP, Pattanaik B, Montgomery BL. RcaE-Dependent Regulation of Carboxysome Structural Proteins Has a Central Role in Environmental Determination of Carboxysome Morphology and Abundance in Fremyella diplosiphon. mSphere 2018; 3:e00617-17. [PMID: 29404416 PMCID: PMC5784247 DOI: 10.1128/msphere.00617-17] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 01/08/2018] [Indexed: 11/20/2022] Open
Abstract
Carboxysomes are central to the carbon dioxide-concentrating mechanism (CCM) and carbon fixation in cyanobacteria. Although the structure is well understood, roles of environmental cues in the synthesis, positioning, and functional tuning of carboxysomes have not been systematically studied. Fremyella diplosiphon is a model cyanobacterium for assessing impacts of environmental light cues on photosynthetic pigmentation and tuning of photosynthetic efficiency during complementary chromatic acclimation (CCA), which is controlled by the photoreceptor RcaE. Given the central role of carboxysomes in photosynthesis, we investigated roles of light-dependent RcaE signaling in carboxysome structure and function. A ΔrcaE mutant exhibits altered carboxysome size and number, ccm gene expression, and carboxysome protein accumulation relative to the wild-type (WT) strain. Several Ccm proteins, including carboxysome shell proteins and core-nucleating factors, overaccumulate in ΔrcaE cells relative to WT cells. Additionally, levels of carboxysome cargo RuBisCO in the ΔrcaE mutant are lower than or unchanged from those in the WT strain. This shift in the ratios of carboxysome shell and nucleating components to the carboxysome cargo appears to drive carboxysome morphology and abundance dynamics. Carboxysomes are also occasionally mislocalized spatially to the periphery of spherical mutants within thylakoid membranes, suggesting that carboxysome positioning is impacted by cell shape. The RcaE photoreceptor links perception of external light cues to regulating carboxysome structure and function and, thus, to the cellular capacity for carbon fixation. IMPORTANCE Carboxysomes are proteinaceous subcellular compartments, or bacterial organelles, found in cyanobacteria that consist of a protein shell surrounding a core primarily composed of the enzyme ribulose-1,5-biphosphate carboxylase/oxygenase (RuBisCO) that is central to the carbon dioxide-concentrating mechanism (CCM) and carbon fixation. Whereas significant insights have been gained regarding the structure and synthesis of carboxysomes, limited attention has been given to how their size, abundance, and protein composition are regulated to ensure optimal carbon fixation in dynamic environments. Given the centrality of carboxysomes in photosynthesis, we provide an analysis of the role of a photoreceptor, RcaE, which functions in matching photosynthetic pigmentation to the external environment during complementary chromatic acclimation and thereby optimizing photosynthetic efficiency, in regulating carboxysome dynamics. Our data highlight a role for RcaE in perceiving external light cues and regulating carboxysome structure and function and, thus, in the cellular capacity for carbon fixation and organismal fitness.
Collapse
Affiliation(s)
- Brandon A. Rohnke
- Department of Energy—Plant Research Laboratory, Michigan State University, Plant Biology Laboratories, East Lansing, Michigan, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, USA
| | - Shailendra P. Singh
- Department of Energy—Plant Research Laboratory, Michigan State University, Plant Biology Laboratories, East Lansing, Michigan, USA
| | - Bagmi Pattanaik
- Department of Energy—Plant Research Laboratory, Michigan State University, Plant Biology Laboratories, East Lansing, Michigan, USA
| | - Beronda L. Montgomery
- Department of Energy—Plant Research Laboratory, Michigan State University, Plant Biology Laboratories, East Lansing, Michigan, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, USA
- Department of Microbiology & Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| |
Collapse
|
43
|
Tomar V, Sidhu GK, Nogia P, Mehrotra R, Mehrotra S. Regulatory components of carbon concentrating mechanisms in aquatic unicellular photosynthetic organisms. PLANT CELL REPORTS 2017; 36:1671-1688. [PMID: 28780704 DOI: 10.1007/s00299-017-2191-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 07/31/2017] [Indexed: 06/07/2023]
Abstract
This review provides an insight into the regulation of the carbon concentrating mechanisms (CCMs) in lower organisms like cyanobacteria, proteobacteria, and algae. CCMs evolved as a mechanism to concentrate CO2 at the site of primary carboxylating enzyme Ribulose-1, 5-bisphosphate carboxylase oxygenase (Rubisco), so that the enzyme could overcome its affinity towards O2 which leads to wasteful processes like photorespiration. A diverse set of CCMs exist in nature, i.e., carboxysomes in cyanobacteria and proteobacteria; pyrenoids in algae and diatoms, the C4 system, and Crassulacean acid metabolism in higher plants. Prime regulators of CCM in most of the photosynthetic autotrophs belong to the LysR family of transcriptional regulators, which regulate the activity of the components of CCM depending upon the ambient CO2 concentrations. Major targets of these regulators are carbonic anhydrase and inorganic carbon uptake systems (CO2 and HCO3- transporters) whose activities are modulated either at transcriptional level or by changes in the levels of their co-regulatory metabolites. The article provides information on the localization of the CCM components as well as their function and participation in the development of an efficient CCM. Signal transduction cascades leading to activation/inactivation of inducible CCM components on perception of low/high CO2 stimuli have also been brought into picture. A detailed study of the regulatory components can aid in identifying the unraveled aspects of these mechanisms and hence provide information on key molecules that need to be explored to further provide a clear understanding of the mechanism under study.
Collapse
Affiliation(s)
- Vandana Tomar
- Department of Biological Sciences, Birla Institute of Technology and Science, Pilani, 333031, Rajasthan, India
| | - Gurpreet Kaur Sidhu
- Department of Biological Sciences, Birla Institute of Technology and Science, Pilani, 333031, Rajasthan, India
| | - Panchsheela Nogia
- Department of Biological Sciences, Birla Institute of Technology and Science, Pilani, 333031, Rajasthan, India
| | - Rajesh Mehrotra
- Department of Biological Sciences, Birla Institute of Technology and Science, Pilani, 333031, Rajasthan, India
| | - Sandhya Mehrotra
- Department of Biological Sciences, Birla Institute of Technology and Science, Pilani, 333031, Rajasthan, India.
| |
Collapse
|
44
|
Niederhuber MJ, Lambert TJ, Yapp C, Silver PA, Polka JK. Superresolution microscopy of the β-carboxysome reveals a homogeneous matrix. Mol Biol Cell 2017; 28:2734-2745. [PMID: 28963440 PMCID: PMC5620380 DOI: 10.1091/mbc.e17-01-0069] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 07/26/2017] [Accepted: 08/02/2017] [Indexed: 11/11/2022] Open
Abstract
Carbon fixation in cyanobacteria makes a major contribution to the global carbon cycle. The cyanobacterial carboxysome is a proteinaceous microcompartment that protects and concentrates the carbon-fixing enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) in a paracrystalline lattice, making it possible for these organisms to fix CO2 from the atmosphere. The protein responsible for the organization of this lattice in beta-type carboxysomes of the freshwater cyanobacterium Synechococcus elongatus, CcmM, occurs in two isoforms thought to localize differentially within the carboxysome matrix. Here we use wide-field time-lapse and three-dimensional structured illumination microscopy (3D-SIM) to study the recruitment and localization of these two isoforms. We demonstrate that this superresolution technique is capable of distinguishing the localizations of the outer protein shell of the carboxysome and its internal cargo. We develop an automated analysis pipeline to analyze and quantify 3D-SIM images and generate a population-level description of the carboxysome shell protein, RuBisCO, and CcmM isoform localization. We find that both CcmM isoforms have similar spatial and temporal localization, prompting a revised model of the internal arrangement of the β-carboxysome.
Collapse
Affiliation(s)
- Matthew J Niederhuber
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115
| | - Talley J Lambert
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115
| | - Clarence Yapp
- Image and Data Analysis Core, Harvard Medical School, Boston, MA 02115
| | - Pamela A Silver
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115
| | - Jessica K Polka
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115
| |
Collapse
|
45
|
Garcia-Alles LF, Lesniewska E, Root K, Aubry N, Pocholle N, Mendoza CI, Bourillot E, Barylyuk K, Pompon D, Zenobi R, Reguera D, Truan G. Spontaneous non-canonical assembly of CcmK hexameric components from β-carboxysome shells of cyanobacteria. PLoS One 2017; 12:e0185109. [PMID: 28934279 PMCID: PMC5608322 DOI: 10.1371/journal.pone.0185109] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 09/06/2017] [Indexed: 02/07/2023] Open
Abstract
CcmK proteins are major constituents of icosahedral shells of β-carboxysomes, a bacterial microcompartment that plays a key role for CO2 fixation in nature. Supported by the characterization of bidimensional (2D) layers of packed CcmK hexamers in crystal and electron microscopy structures, CcmK are assumed to be the major components of icosahedral flat facets. Here, we reassessed the validity of this model by studying CcmK isoforms from Synechocystis sp. PCC6803. Native mass spectrometry studies confirmed that CcmK are hexamers in solution. Interestingly, potential pre-assembled intermediates were also detected with CcmK2. Atomic-force microscopy (AFM) imaging under quasi-physiological conditions confirmed the formation of canonical flat sheets with CcmK4. Conversely, CcmK2 formed both canonical and striped-patterned patches, while CcmK1 assembled into remarkable supra-hexameric curved honeycomb-like mosaics. Mutational studies ascribed the propensity of CcmK1 to form round assemblies to a combination of two features shared by at least one CcmK isoform in most β-cyanobacteria: a displacement of an α helical portion towards the hexamer edge, where a potential phosphate binding funnel forms between packed hexamers, and the presence of a short C-terminal extension in CcmK1. All-atom molecular dynamics supported a contribution of phosphate molecules sandwiched between hexamers to bend CcmK1 assemblies. Formation of supra-hexameric curved structures could be reproduced in coarse-grained simulations, provided that adhesion forces to the support were weak. Apart from uncovering unprecedented CcmK self-assembly features, our data suggest the possibility that transitions between curved and flat assemblies, following cargo maturation, could be important for the biogenesis of β-carboxysomes, possibly also of other BMC.
Collapse
Affiliation(s)
- Luis F. Garcia-Alles
- LISBP, CNRS, INRA, INSA, University of Toulouse, Toulouse, France
- * E-mail: (LFGA); (GT)
| | - Eric Lesniewska
- ICB UMR CNRS 6303, University of Bourgogne Franche-Comte, Dijon, France
| | - Katharina Root
- Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich, Switzerland
| | - Nathalie Aubry
- LISBP, CNRS, INRA, INSA, University of Toulouse, Toulouse, France
| | - Nicolas Pocholle
- ICB UMR CNRS 6303, University of Bourgogne Franche-Comte, Dijon, France
| | - Carlos I. Mendoza
- Departament de Física de la Matèria Condensada, Universitat de Barcelona, Barcelona, Spain
- Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, Cd Mx, México
| | - Eric Bourillot
- ICB UMR CNRS 6303, University of Bourgogne Franche-Comte, Dijon, France
| | - Konstantin Barylyuk
- Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich, Switzerland
| | - Denis Pompon
- LISBP, CNRS, INRA, INSA, University of Toulouse, Toulouse, France
| | - Renato Zenobi
- Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich, Switzerland
| | - David Reguera
- Departament de Física de la Matèria Condensada, Universitat de Barcelona, Barcelona, Spain
| | - Gilles Truan
- LISBP, CNRS, INRA, INSA, University of Toulouse, Toulouse, France
- * E-mail: (LFGA); (GT)
| |
Collapse
|
46
|
Matsuda Y, Hopkinson BM, Nakajima K, Dupont CL, Tsuji Y. Mechanisms of carbon dioxide acquisition and CO 2 sensing in marine diatoms: a gateway to carbon metabolism. Philos Trans R Soc Lond B Biol Sci 2017; 372:20160403. [PMID: 28717013 PMCID: PMC5516112 DOI: 10.1098/rstb.2016.0403] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/31/2017] [Indexed: 01/03/2023] Open
Abstract
Diatoms are one of the most successful marine eukaryotic algal groups, responsible for up to 20% of the annual global CO2 fixation. The evolution of a CO2-concentrating mechanism (CCM) allowed diatoms to overcome a number of serious constraints on photosynthesis in the marine environment, particularly low [CO2]aq in seawater relative to concentrations required by the CO2 fixing enzyme, ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO), which is partly due to the slow diffusion rate of CO2 in water and a limited CO2 formation rate from [Formula: see text] in seawater. Diatoms use two alternative strategies to take up dissolved inorganic carbon (DIC) from the environment: one primarily relies on the direct uptake of [Formula: see text] through plasma-membrane type solute carrier (SLC) 4 family [Formula: see text] transporters and the other is more reliant on passive diffusion of CO2 formed by an external carbonic anhydrase (CA). Bicarbonate taken up into the cytoplasm is most likely then actively transported into the chloroplast stroma by SLC4-type transporters on the chloroplast membrane system. Bicarbonate in the stroma is converted into CO2 only in close proximity to RubisCO preventing unnecessary CO2 leakage. CAs play significant roles in mobilizing DIC as it is progressively moved towards the site of fixation. However, the evolutionary types and subcellular locations of CAs are not conserved between different diatoms, strongly suggesting that this DIC mobilization strategy likely evolved multiple times with different origins. By contrast, the recent discovery of the thylakoid luminal θ-CA indicates that the strategy to supply CO2 to RubisCO in the pyrenoid may be very similar to that of green algae, and strongly suggests convergent coevolution in CCM function of the thylakoid lumen not only among diatoms but among eukaryotic algae in general. In this review, both experimental and corresponding theoretical models of the diatom CCMs are discussed.This article is part of the themed issue 'The peculiar carbon metabolism in diatoms'.
Collapse
Affiliation(s)
- Yusuke Matsuda
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, Hyogo 669-1337, Japan
| | - Brian M Hopkinson
- Department of Marine Sciences, University of Georgia, Athens, GA 30602, USA
| | - Kensuke Nakajima
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, Hyogo 669-1337, Japan
| | | | - Yoshinori Tsuji
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, Hyogo 669-1337, Japan
| |
Collapse
|
47
|
Turmo A, Gonzalez-Esquer CR, Kerfeld CA. Carboxysomes: metabolic modules for CO2 fixation. FEMS Microbiol Lett 2017; 364:4082729. [DOI: 10.1093/femsle/fnx176] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 08/12/2017] [Indexed: 11/13/2022] Open
|
48
|
Kaplan A. On the cradle of CCM research: discovery, development, and challenges ahead. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:3785-3796. [PMID: 28520892 DOI: 10.1093/jxb/erx122] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Herein, 40 years after its discovery, I briefly and critically survey the development of ideas that propelled research on CO2-concentrating mechanisms (CCMs; a term proposed by Dean Price) of phytoplankton, mainly focusing on cyanobacteria. This is not a comprehensive review on CCM research, but a personal view on the past developments and challenges that lie ahead.
Collapse
Affiliation(s)
- Aaron Kaplan
- Department of Plant and Environmental Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, 9190401, Israel
| |
Collapse
|
49
|
Tsuji Y, Nakajima K, Matsuda Y. Molecular aspects of the biophysical CO2-concentrating mechanism and its regulation in marine diatoms. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:3763-3772. [PMID: 28633304 DOI: 10.1093/jxb/erx173] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Diatoms operate a CO2-concentrating mechanism (CCM) that drives upwards of 20% of annual global primary production. Recent progress in CCM research in the marine pennate diatom Phaeodactylum tricornutum revealed that this diatom directly takes up HCO3- from seawater through low-CO2-inducible plasma membrane HCO3- transporters, which belong to the solute carrier (SLC) 4 family. Apart from this, studies of carbonic anhydrases (CAs) in diatoms have revealed considerable diversity in classes and localization among species. This strongly suggests that the CA systems, which control permeability and flux of dissolved inorganic carbon (DIC) by catalysing reversible CO2 hydration, have evolved from diverse origins. Of particular interest is the occurrence of low-CO2-inducible external CAs in the centric marine diatom Thalassiosira pseudonana, offering a strategy of CA-catalysed initial CO2 entry via passive diffusion, contrasting with active DIC transport in P. tricornutum. Molecular mechanisms to transport DIC across chloroplast envelopes are likely also through specific HCO3- transporters, although details have yet to be elucidated. Furthermore, recent discovery of a luminal θ-CA in the diatom thylakoid implied a common strategy in the mechanism to supply CO2 to RubisCO in the pyrenoid, which is conserved among green algae and some heterokontophytes. These results strongly suggest an occurrence of convergent coevolution between the pyrenoid and thylakoid membrane in aquatic photosynthesis.
Collapse
Affiliation(s)
- Yoshinori Tsuji
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, Hyogo 669-1337, Japan
| | - Kensuke Nakajima
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, Hyogo 669-1337, Japan
| | - Yusuke Matsuda
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, Hyogo 669-1337, Japan
| |
Collapse
|
50
|
Sommer M, Cai F, Melnicki M, Kerfeld CA. β-Carboxysome bioinformatics: identification and evolution of new bacterial microcompartment protein gene classes and core locus constraints. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:3841-3855. [PMID: 28419380 PMCID: PMC5853843 DOI: 10.1093/jxb/erx115] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 03/18/2017] [Indexed: 05/03/2023]
Abstract
Carboxysomes are bacterial microcompartments (BMCs) that enhance CO2 fixation in all cyanobacteria. Structurally, carboxysome shell proteins are classified according to the type of oligomer formed: hexameric (BMC-H), trimeric (BMC-T) and pentameric (BMC-P) proteins. To understand the forces driving the evolution of the carboxysome shell, we conducted a bioinformatic study of genes encoding β-carboxysome shell proteins, taking advantage of the recent large increase in sequenced cyanobacterial genomes. In addition to the four well-established BMC-H (CcmK1-4) classes, our analysis reveals two new CcmK classes, which we name CcmK5 and CcmK6. CcmK5 is phylogenetically closest to CcmK3 and CcmK4, and the ccmK5 gene is found only in genomes lacking ccmK3 and ccmk4 genes. ccmK6 is found predominantly in heterocyst-forming cyanobacteria. The gene encoding the BMC-T homolog CcmO is associated with the main carboxysome locus (MCL) in only 60% of all species. We find five evolutionary origins of separation of ccmO from the MCL. Transcriptome analysis demonstrates that satellite ccmO genes, in contrast to MCL-associated ccmO genes, are never co-regulated with other MCL genes. The dispersal of carboxysome shell genes across the genome allows for distinct regulation of their expression, perhaps in response to changes in environmental conditions.
Collapse
Affiliation(s)
- Manuel Sommer
- Department of Plant and Microbial Biology, UC Berkeley, Berkeley, CA, USA
- MBIB Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Fei Cai
- Department of Plant and Microbial Biology, UC Berkeley, Berkeley, CA, USA
- MBIB Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Matthew Melnicki
- MSU-DOE Plant Research Laboratory and Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA
- MBIB Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Cheryl A Kerfeld
- Department of Plant and Microbial Biology, UC Berkeley, Berkeley, CA, USA
- MSU-DOE Plant Research Laboratory and Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA
- MBIB Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| |
Collapse
|