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Gisriel CJ, Elias E, Shen G, Soulier NT, Flesher DA, Gunner MR, Brudvig GW, Croce R, Bryant DA. Helical allophycocyanin nanotubes absorb far-red light in a thermophilic cyanobacterium. SCIENCE ADVANCES 2023; 9:eadg0251. [PMID: 36961897 PMCID: PMC10038336 DOI: 10.1126/sciadv.adg0251] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 02/24/2023] [Indexed: 06/18/2023]
Abstract
To compete in certain low-light environments, some cyanobacteria express a paralog of the light-harvesting phycobiliprotein, allophycocyanin (AP), that strongly absorbs far-red light (FRL). Using cryo-electron microscopy and time-resolved absorption spectroscopy, we reveal the structure-function relationship of this FRL-absorbing AP complex (FRL-AP) that is expressed during acclimation to low light and that likely associates with chlorophyll a-containing photosystem I. FRL-AP assembles as helical nanotubes rather than typical toroids due to alterations of the domain geometry within each subunit. Spectroscopic characterization suggests that FRL-AP nanotubes are somewhat inefficient antenna; however, the enhanced ability to harvest FRL when visible light is severely attenuated represents a beneficial trade-off. The results expand the known diversity of light-harvesting proteins in nature and exemplify how biological plasticity is achieved by balancing resource accessibility with efficiency.
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Affiliation(s)
| | - Eduard Elias
- Department of Physics and Astronomy, and LaserLaB Amsterdam, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Gaozhong Shen
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Nathan T. Soulier
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - David A. Flesher
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - M. R. Gunner
- Department of Physics, City College of New York, New York, NY 10031, USA
| | - Gary W. Brudvig
- Department of Chemistry, Yale University, New Haven, CT 06520, USA
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Roberta Croce
- Department of Physics and Astronomy, and LaserLaB Amsterdam, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Donald A. Bryant
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
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2
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cKMT1 is a new lysine methyltransferase that methylates the ferredoxin-NADP(+) oxidoreductase (FNR) and regulates energy transfer in cyanobacteria. Mol Cell Proteomics 2023; 22:100521. [PMID: 36858286 PMCID: PMC10090440 DOI: 10.1016/j.mcpro.2023.100521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2022] [Revised: 02/20/2023] [Accepted: 02/24/2023] [Indexed: 03/03/2023] Open
Abstract
Lysine methylation is a conserved and dynamic regulatory post-translational modification performed by lysine methyltransferases (KMTs). KMTs catalyze the transfer of mono-, di-, or tri-methyl groups to substrate proteins and play a critical regulatory role in all domains of life. To date, only one KMT has been identified in cyanobacteria. Here, we tested all of the predicted KMTs in the cyanobacterium Synechocystis sp. PCC 6803 (Synechocystis), and we biochemically characterized sll1526 that we termed cKMT1 (cyanobacterial lysine methyltransferase 1), and determined that it can catalyze lysine methylation both in vivo and in vitro. Loss of cKMT1 alters photosynthetic electron transfer in Synechocystis. We analyzed cKMT1-regulated methylation sites in Synechocystis using a timsTOF Pro instrument. We identified 305 class I lysine methylation sites within 232 proteins, and of these, 80 methylation sites in 58 proteins were hypomethylated in ΔcKMT1 cells. We further demonstrated that cKMT1 could methylate ferredoxin-NADP(+) oxidoreductase (FNR) and its potential sites of action on FNR were identified. Amino acid residues H118 and Y219 were identified as key residues in the putative active site of cKMT1 as indicated by structure simulation, site-directed mutagenesis, and KMT activity measurement. Using mutations that mimic the unmethylated forms of FNR, we demonstrated that the inability to methylate K139 residues results in a decrease in the redox activity of FNR and affects energy transfer in Synechocystis. Together, our study identified a new KMT in Synechocystis and elucidated a methylation-mediated molecular mechanism catalyzed by cKMT1 for the regulation of energy transfer in cyanobacteria.
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3
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Lin X, Yang M, Liu X, Cheng Z, Ge F. Characterization of Lysine Monomethylome and Methyltransferase in Model Cyanobacterium Synechocystis sp. PCC 6803. GENOMICS PROTEOMICS & BIOINFORMATICS 2020; 18:289-304. [PMID: 33130100 PMCID: PMC7801250 DOI: 10.1016/j.gpb.2019.04.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 03/03/2019] [Accepted: 04/19/2019] [Indexed: 12/25/2022]
Abstract
Protein lysine methylation is a prevalent post-translational modification (PTM) and plays critical roles in all domains of life. However, its extent and function in photosynthetic organisms are still largely unknown. Cyanobacteria are a large group of prokaryotes that carry out oxygenic photosynthesis and are applied extensively in studies of photosynthetic mechanisms and environmental adaptation. Here we integrated propionylation of monomethylated proteins, enrichment of the modified peptides, and mass spectrometry (MS) analysis to identify monomethylated proteins in Synechocystis sp. PCC 6803 (Synechocystis). Overall, we identified 376 monomethylation sites in 270 proteins, with numerous monomethylated proteins participating in photosynthesis and carbon metabolism. We subsequently demonstrated that CpcM, a previously identified asparagine methyltransferase in Synechocystis, could catalyze lysine monomethylation of the potential aspartate aminotransferase Sll0480 both in vivo and in vitro and regulate the enzyme activity of Sll0480. The loss of CpcM led to decreases in the maximum quantum yield in primary photosystem II (PSII) and the efficiency of energy transfer during the photosynthetic reaction in Synechocystis. We report the first lysine monomethylome in a photosynthetic organism and present a critical database for functional analyses of monomethylation in cyanobacteria. The large number of monomethylated proteins and the identification of CpcM as the lysine methyltransferase in cyanobacteria suggest that reversible methylation may influence the metabolic process and photosynthesis in both cyanobacteria and plants.
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Affiliation(s)
- Xiaohuang Lin
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing 100039, China
| | - Mingkun Yang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Xin Liu
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing 100039, China
| | - Zhongyi Cheng
- Jingjie PTM BioLab (Hangzhou) Co. Ltd, Hangzhou 310018, China
| | - Feng Ge
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
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4
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Wahadoszamen M, Krüger TPJ, Ara AM, van Grondelle R, Gwizdala M. Charge transfer states in phycobilisomes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1861:148187. [PMID: 32173383 DOI: 10.1016/j.bbabio.2020.148187] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 02/17/2020] [Accepted: 03/09/2020] [Indexed: 10/24/2022]
Abstract
Phycobilisomes (PBs) absorb light and supply downstream photosynthetic processes with excitation energy in many cyanobacteria and algae. In response to a sudden increase in light intensity, excess excitation energy is photoprotectively dissipated in PBs by means of the orange carotenoid protein (OCP)-related mechanism or via a light-activated intrinsic decay channel. Recently, we have identified that both mechanisms are associated with far-red emission states. Here, we investigate the far-red states involved with the light-induced intrinsic mechanism by exploring the energy landscape and electro-optical properties of the pigments in PBs. While Stark spectroscopy showed that the far-red states in PBs exhibit a strong charge-transfer (CT) character at cryogenic temperatures, single molecule spectroscopy revealed that CT states should also be present at room temperature. Owing to the strong environmental sensitivity of CT states, the knowledge gained from this study may contribute to the design of a new generation of fluorescence markers.
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Affiliation(s)
- Md Wahadoszamen
- Department of Physics, University of Dhaka, Dhaka 1000, Bangladesh
| | - Tjaart P J Krüger
- Department of Physics, University of Pretoria, Pretoria 0023, South Africa
| | - Anjue Mane Ara
- Department of Physics, Jagannath University, Dhaka 1100, Bangladesh
| | - Rienk van Grondelle
- Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam 1081 HV, the Netherlands
| | - Michal Gwizdala
- Department of Physics, University of Pretoria, Pretoria 0023, South Africa; Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam 1081 HV, the Netherlands.
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5
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Kronfel CM, Biswas A, Frick JP, Gutu A, Blensdorf T, Karty JA, Kehoe DM, Schluchter WM. The roles of the chaperone-like protein CpeZ and the phycoerythrobilin lyase CpeY in phycoerythrin biogenesis. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2019; 1860:549-561. [PMID: 31173730 DOI: 10.1016/j.bbabio.2019.06.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 04/26/2019] [Accepted: 06/02/2019] [Indexed: 02/08/2023]
Abstract
Phycoerythrin (PE) present in the distal ends of light-harvesting phycobilisome rods in Fremyella diplosiphon (Tolypothrix sp. PCC 7601) contains five phycoerythrobilin (PEB) chromophores attached to six cysteine residues for efficient green light capture for photosynthesis. Chromophore ligation on PE subunits occurs through bilin lyase catalyzed reactions, but the characterization of the roles of all bilin lyases for phycoerythrin is not yet complete. To gain a more complete understanding about the individual functions of CpeZ and CpeY in PE biogenesis in cyanobacteria, we examined PE and phycobilisomes purified from wild type F. diplosiphon, cpeZ and cpeY knockout mutants. We find that the cpeZ and cpeY mutants accumulate less PE than wild type cells. We show that in the cpeZ mutant, chromophorylation of both PE subunits is affected, especially the Cys-80 and Cys-48/Cys-59 sites of CpeB, the beta-subunit of PE. The cpeY mutant showed reduced chromophorylation at Cys-82 of CpeA. We also show that, in vitro, CpeZ stabilizes PE subunits and assists in refolding of CpeB after denaturation. Taken together, we conclude that CpeZ acts as a chaperone-like protein, assisting in the folding/stability of PE subunits, allowing bilin lyases such as CpeY and CpeS to attach PEB to their PE subunit.
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Affiliation(s)
- Christina M Kronfel
- Department of Biological Sciences, University of New Orleans, New Orleans, LA 70148, USA
| | - Avijit Biswas
- Department of Chemistry, University of New Orleans, New Orleans, LA 70148, USA
| | - Jacob P Frick
- Department of Biological Sciences, University of New Orleans, New Orleans, LA 70148, USA
| | - Andrian Gutu
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - Tyler Blensdorf
- Department of Chemistry, Indiana University, Bloomington, IN 47405, USA
| | - Jonathan A Karty
- Department of Chemistry, Indiana University, Bloomington, IN 47405, USA
| | - David M Kehoe
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - Wendy M Schluchter
- Department of Biological Sciences, University of New Orleans, New Orleans, LA 70148, USA.
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6
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Bar-Zvi S, Lahav A, Harris D, Niedzwiedzki DM, Blankenship RE, Adir N. Structural heterogeneity leads to functional homogeneity in A. marina phycocyanin. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1859:544-553. [DOI: 10.1016/j.bbabio.2018.04.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 04/18/2018] [Accepted: 04/23/2018] [Indexed: 12/31/2022]
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7
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Sirota FL, Maurer-Stroh S, Eisenhaber B, Eisenhaber F. Single-residue posttranslational modification sites at the N-terminus, C-terminus or in-between: To be or not to be exposed for enzyme access. Proteomics 2016; 15:2525-46. [PMID: 26038108 PMCID: PMC4745020 DOI: 10.1002/pmic.201400633] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Revised: 04/17/2015] [Accepted: 05/29/2015] [Indexed: 11/30/2022]
Abstract
Many protein posttranslational modifications (PTMs) are the result of an enzymatic reaction. The modifying enzyme has to recognize the substrate protein's sequence motif containing the residue(s) to be modified; thus, the enzyme's catalytic cleft engulfs these residue(s) and the respective sequence environment. This residue accessibility condition principally limits the range where enzymatic PTMs can occur in the protein sequence. Non‐globular, flexible, intrinsically disordered segments or large loops/accessible long side chains should be preferred whereas residues buried in the core of structures should be void of what we call canonical, enzyme‐generated PTMs. We investigate whether PTM sites annotated in UniProtKB (with MOD_RES/LIPID keys) are situated within sequence ranges that can be mapped to known 3D structures. We find that N‐ or C‐termini harbor essentially exclusively canonical PTMs. We also find that the overwhelming majority of all other PTMs are also canonical though, later in the protein's life cycle, the PTM sites can become buried due to complex formation. Among the remaining cases, some can be explained (i) with autocatalysis, (ii) with modification before folding or after temporary unfolding, or (iii) as products of interaction with small, diffusible reactants. Others require further research how these PTMs are mechanistically generated in vivo.
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Affiliation(s)
- Fernanda L Sirota
- Bioinformatics Institute (BII), Agency for Science and Technology (A*STAR), Matrix, Singapore
| | - Sebastian Maurer-Stroh
- Bioinformatics Institute (BII), Agency for Science and Technology (A*STAR), Matrix, Singapore.,School of Biological Sciences (SBS), Nanyang Technological University (NTU), Singapore
| | - Birgit Eisenhaber
- Bioinformatics Institute (BII), Agency for Science and Technology (A*STAR), Matrix, Singapore
| | - Frank Eisenhaber
- Bioinformatics Institute (BII), Agency for Science and Technology (A*STAR), Matrix, Singapore.,Department of Biological Sciences (DBS), National University of Singapore (NUS), Singapore.,School of Computer Engineering (SCE), Nanyang Technological University (NTU), Singapore
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8
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Chen Z, Zhan J, Chen Y, Yang M, He C, Ge F, Wang Q. Effects of Phosphorylation of β Subunits of Phycocyanins on State Transition in the Model Cyanobacterium Synechocystis sp. PCC 6803. PLANT & CELL PHYSIOLOGY 2015; 56:1997-2013. [PMID: 26315596 DOI: 10.1093/pcp/pcv118] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 08/09/2015] [Indexed: 05/22/2023]
Abstract
Synechocystis sp. PCC 6803 (hereafter Synechocystis) is a model cyanobacterium and has been used extensively for studies concerned with photosynthesis and environmental adaptation. Although dozens of protein kinases and phosphatases with specificity for Ser/Thr/Tyr residues have been predicted, only a few substrate proteins are known in Synechocystis. In this study, we report 194 in vivo phosphorylation sites from 149 proteins in Synechocystis, which were identified using a combination of peptide pre-fractionation, TiO(2) enrichment and liquid chromatograpy-tandem mass spectrometry (LC-MS/MS) analysis. These phosphorylated proteins are implicated in diverse biological processes, such as photosynthesis. Among all identified phosphoproteins involved in photosynthesis, the β subunits of phycocyanins (CpcBs) were found to be phosphorylated on Ser22, Ser49, Thr94 and Ser154. Four non-phosphorylated mutants were constructed by using site-directed mutagenesis. The in vivo characterization of the cpcB mutants showed a slower growth under high light irradiance and displayed fluorescence quenching to a lower level and less efficient energy transfer inside the phycobilisome (PBS). Notably, the non-phosphorylated mutants exhibited a slower state transition than the wild type. The current results demonstrated that the phosphorylation status of CpcBs affects the energy transfer and state transition of photosynthesis in Synechocystis. This study provides novel insights into the molecular mechanisms of protein phosphorylation in the regulation of photosynthesis in cyanobacteria and may facilitate the elucidation of the entire regulatory network by linking kinases to their physiological substrates.
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Affiliation(s)
- Zhuo Chen
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, Hubei, China These authors contributed equally to this work.
| | - Jiao Zhan
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, Hubei, China University of Chinese Academy of Sciences, Beijing 100094, China These authors contributed equally to this work.
| | - Ying Chen
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, Hubei, China
| | - Mingkun Yang
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, Hubei, China
| | - Chenliu He
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, Hubei, China
| | - Feng Ge
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, Hubei, China
| | - Qiang Wang
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, Hubei, China
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9
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Marx A, Adir N. Allophycocyanin and phycocyanin crystal structures reveal facets of phycobilisome assembly. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012. [PMID: 23201474 DOI: 10.1016/j.bbabio.2012.11.006] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
X-ray crystal structures of the isolated phycobiliprotein components of the phycobilisome have provided high resolution details to the description of this light harvesting complex at different levels of complexity and detail. The linker-independent assembly of trimers into hexamers in crystal lattices of previously determined structures has been observed in almost all of the phycocyanin (PC) and allophycocyanin (APC) structures available in the Protein Data Bank. In this paper we describe the X-ray crystal structures of PC and APC from Synechococcus elongatus sp. PCC 7942, PC from Synechocystis sp. PCC 6803 and PC from Thermosynechococcus vulcanus crystallized in the presence of urea. All five structures are highly similar to other PC and APC structures on the levels of subunits, monomers and trimers. The Synechococcus APC forms a unique loose hexamer that may show the structural requirements for core assembly and rod attachment. While the Synechococcus PC assembles into the canonical hexamer, it does not further assemble into rods. Unlike most PC structures, the Synechocystis PC fails to form hexamers. Addition of low concentrations of urea to T. vulcanus PC inhibits this proteins propensity to form hexamers, resulting in a crystal lattice composed of trimers. The molecular source of these differences in assembly and their relevance to the phycobilisome structure is discussed.
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Affiliation(s)
- Ailie Marx
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa, Israel
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10
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Freeman MF, Gurgui C, Helf MJ, Morinaka BI, Uria AR, Oldham NJ, Sahl HG, Matsunaga S, Piel J. Metagenome mining reveals polytheonamides as posttranslationally modified ribosomal peptides. Science 2012; 338:387-90. [PMID: 22983711 DOI: 10.1126/science.1226121] [Citation(s) in RCA: 257] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
It is held as a paradigm that ribosomally synthesized peptides and proteins contain only l-amino acids. We demonstrate a ribosomal origin of the marine sponge-derived polytheonamides, exceptionally potent, giant natural-product toxins. Isolation of the biosynthetic genes from the sponge metagenome revealed a bacterial gene architecture. Only six candidate enzymes were identified for 48 posttranslational modifications, including 18 epimerizations and 17 methylations of nonactivated carbon centers. Three enzymes were functionally validated, which showed that a radical S-adenosylmethionine enzyme is responsible for the unidirectional epimerization of multiple and different amino acids. Collectively, these complex alterations create toxins that function as unimolecular minimalistic ion channels with near-femtomolar activity. This study broadens the biosynthetic scope of ribosomal systems and creates new opportunities for peptide and protein bioengineering.
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Affiliation(s)
- Michael F Freeman
- Kekulé Institute of Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Strasse 1, 53121 Bonn, Germany
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11
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Xu Y, Alvey RM, Byrne PO, Graham JE, Shen G, Bryant DA. Expression of genes in cyanobacteria: adaptation of endogenous plasmids as platforms for high-level gene expression in Synechococcus sp. PCC 7002. Methods Mol Biol 2011; 684:273-93. [PMID: 20960136 DOI: 10.1007/978-1-60761-925-3_21] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Synechococcus sp. PCC 7002 is an ideal model cyanobacterium for functional genomics and biotechnological applications through metabolic engineering. A gene expression system that takes advantage of its multiple, endogenous plasmids has been constructed in this cyanobacterium. The method involves the integration of foreign DNA cassettes with selectable markers into neutral sites that can be located on any of the several endogenous plasmids of this organism. We have exploited the natural transformability and powerful homologous recombination capacity of this organism by using linear DNA fragments for transformation. This approach overcomes barriers that have made the introduction and expression of foreign genes problematic in the past. Foremost among these is the natural restriction endonuclease barrier that can cleave transforming circular plasmid DNAs before they can be replicated in the cell. We describe herein the general methodology for expressing foreign and homologous genes in Synechococcus sp. PCC 7002, a comparison of several commonly used promoters, and provide examples of how this approach has successfully been used in complementation analyses and overproduction of proteins with affinity tags.
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Affiliation(s)
- Yu Xu
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
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12
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Biswas A, Vasquez YM, Dragomani TM, Kronfel ML, Williams SR, Alvey RM, Bryant DA, Schluchter WM. Biosynthesis of cyanobacterial phycobiliproteins in Escherichia coli: chromophorylation efficiency and specificity of all bilin lyases from Synechococcus sp. strain PCC 7002. Appl Environ Microbiol 2010; 76:2729-39. [PMID: 20228104 PMCID: PMC2863458 DOI: 10.1128/aem.03100-09] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2009] [Accepted: 03/01/2010] [Indexed: 11/20/2022] Open
Abstract
Phycobiliproteins are water-soluble, light-harvesting proteins that are highly fluorescent due to linear tetrapyrrole chromophores, which makes them valuable as probes. Enzymes called bilin lyases usually attach these bilin chromophores to specific cysteine residues within the alpha and beta subunits via thioether linkages. A multiplasmid coexpression system was used to recreate the biosynthetic pathway for phycobiliproteins from the cyanobacterium Synechococcus sp. strain PCC 7002 in Escherichia coli. This system efficiently produced chromophorylated allophycocyanin (ApcA/ApcB) and alpha-phycocyanin with holoprotein yields ranging from 3 to 12 mg liter(-1) of culture. This heterologous expression system was used to demonstrate that the CpcS-I and CpcU proteins are both required to attach phycocyanobilin (PCB) to allophycocyanin subunits ApcD (alpha(AP-B)) and ApcF (beta(18)). The N-terminal, allophycocyanin-like domain of ApcE (L(CM)(99)) was produced in soluble form and was shown to have intrinsic bilin lyase activity. Lastly, this in vivo system was used to evaluate the efficiency of the bilin lyases for production of beta-phycocyanin.
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Affiliation(s)
- Avijit Biswas
- Department of Biological Science, University of New Orleans, New Orleans, Louisiana 70148, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - Yasmin M. Vasquez
- Department of Biological Science, University of New Orleans, New Orleans, Louisiana 70148, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - Tierna M. Dragomani
- Department of Biological Science, University of New Orleans, New Orleans, Louisiana 70148, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - Monica L. Kronfel
- Department of Biological Science, University of New Orleans, New Orleans, Louisiana 70148, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - Shervonda R. Williams
- Department of Biological Science, University of New Orleans, New Orleans, Louisiana 70148, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - Richard M. Alvey
- Department of Biological Science, University of New Orleans, New Orleans, Louisiana 70148, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - Donald A. Bryant
- Department of Biological Science, University of New Orleans, New Orleans, Louisiana 70148, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - Wendy M. Schluchter
- Department of Biological Science, University of New Orleans, New Orleans, Louisiana 70148, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802
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13
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Schluchter WM, Shen G, Alvey RM, Biswas A, Saunée NA, Williams SR, Mille CA, Bryant DA. Phycobiliprotein biosynthesis in cyanobacteria: structure and function of enzymes involved in post-translational modification. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 675:211-28. [PMID: 20532743 DOI: 10.1007/978-1-4419-1528-3_12] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Cyanobacterial phycobiliproteins are brilliantly colored due to the presence of covalently attached chromophores called bilins, linear tetrapyrroles derived from heme. For most phycobiliproteins, these post-translational modifications are catalyzed by enzymes called bilin lyases; these enzymes ensure that the appropriate bilins are attached to the correct cysteine residues with the proper stereochemistry on each phycobiliprotein subunit. Phycobiliproteins also contain a unique, post-translational modification, the methylation of a conserved asparagine (Asn) present at beta-72, which occurs on the beta-subunits of all phycobiliproteins. We have identified and characterized several new families of bilin lyases, which are responsible for attaching PCB to phycobiliproteins as well as the Asn methyl transferase for beta-subunits in Synechococcus sp. PCC 7002 and Synechocystis sp. PCC 6803. All of the enzymes responsible for synthesis of holo-phycobiliproteins are now known for this cyanobacterium, and a brief discussion of each enzyme family and its role in the biosynthesis of phycobiliproteins is presented here. In addition, the first structure of a bilin lyase has recently been solved (PDB ID: 3BDR). This structure shows that the bilin lyases are most similar to the lipocalin protein structural family, which also includes the bilin-binding protein found in some butterflies.
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Affiliation(s)
- Wendy M Schluchter
- Department of Biological Sciences, University of New Orleans, New Orleans, LA 70148, USA.
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Blot N, Wu XJ, Thomas JC, Zhang J, Garczarek L, Böhm S, Tu JM, Zhou M, Plöscher M, Eichacker L, Partensky F, Scheer H, Zhao KH. Phycourobilin in trichromatic phycocyanin from oceanic cyanobacteria is formed post-translationally by a phycoerythrobilin lyase-isomerase. J Biol Chem 2009; 284:9290-8. [PMID: 19182270 DOI: 10.1074/jbc.m809784200] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Most cyanobacteria harvest light with large antenna complexes called phycobilisomes. The diversity of their constituting phycobiliproteins contributes to optimize the photosynthetic capacity of these microorganisms. Phycobiliprotein biosynthesis, which involves several post-translational modifications including covalent attachment of the linear tetrapyrrole chromophores (phycobilins) to apoproteins, begins to be well understood. However, the biosynthetic pathway to the blue-green-absorbing phycourobilin (lambda(max) approximately 495 nm) remained unknown, although it is the major phycobilin of cyanobacteria living in oceanic areas where blue light penetrates deeply into the water column. We describe a unique trichromatic phycocyanin, R-PC V, extracted from phycobilisomes of Synechococcus sp. strain WH8102. It is evolutionarily remarkable as the only chromoprotein known so far that absorbs the whole wavelength range between 450 and 650 nm. R-PC V carries a phycourobilin chromophore on its alpha-subunit, and this can be considered an extreme case of adaptation to blue-green light. We also discovered the enzyme, RpcG, responsible for its biosynthesis. This monomeric enzyme catalyzes binding of the green-absorbing phycoerythrobilin at cysteine 84 with concomitant isomerization to phycourobilin. This reaction is analogous to formation of the orange-absorbing phycoviolobilin from the red-absorbing phycocyanobilin that is catalyzed by the lyase-isomerase PecE/F in some freshwater cyanobacteria. The fusion protein, RpcG, and the heterodimeric PecE/F are mutually interchangeable in a heterologous expression system in Escherichia coli. The novel R-PC V likely optimizes rod-core energy transfer in phycobilisomes and thereby adaptation of a major phytoplankton group to the blue-green light prevailing in oceanic waters.
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Affiliation(s)
- Nicolas Blot
- UPMC-Université Paris 06, Station Biologique, 29682 Roscoff, France, CNRS, UMR 7144, Groupe Plancton Océanique, 29682 Roscoff, France
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Allophycocyanin trimer stability and functionality are primarily due to polar enhanced hydrophobicity of the phycocyanobilin binding pocket. J Mol Biol 2008; 384:406-21. [PMID: 18823993 DOI: 10.1016/j.jmb.2008.09.018] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2008] [Revised: 09/04/2008] [Accepted: 09/10/2008] [Indexed: 11/22/2022]
Abstract
Allophycocyanin (APC) is the primary pigment-protein component of the cores of the phycobilisome antenna complex. In addition to an extremely high degree of amino acid sequence conservation, the overall structures of APC from both mesophilic and thermophilic species are almost identical at all levels of assembly, yet APC from thermophilic organisms should have structural attributes that prevent thermally induced denaturation. We determined the structure of APC from the thermophilic cyanobacterium Thermosynechococcus vulcanus to 2.9 A, reaffirming the conservation of structural similarity with APC from mesophiles. We provide spectroscopic evidence that T. vulcanus APC is indeed more stable at elevated temperatures in vitro, when compared with the APC from mesophilic species. APC thermal and chemical stability levels are further enhanced when monitored in the presence of high concentrations of buffered phosphate, which increases the strength of hydrophobic interactions, and may mimic the effect of cytosolic crowding. Absorption spectroscopy, size-exclusion HPLC, and native gel electrophoresis also show that the thermally or chemically induced changes in the APC absorption spectra that result in the loss of the prominent 652-nm band in trimeric APC are not a result of physical monomerization. We propose that the bathochromic shift that occurs in APC upon trimerization is due to the coupling of the hydrophobicity of the alpha84 phycocyanobilin cofactor environment created by a deep cleft formed by the beta subunit with highly charged flanking regions. This arrangement also provides the additional stability required by thermophiles at elevated temperatures. The chemical environment that induces the bathochromic shift in APC trimers is different from the source of shifts in the absorption of monomers of the terminal energy acceptors APC(B) and L(CM), as visualized by the building of molecular models.
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