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Wang YT, Yang CH, Huang KS, Shaw JF. Chlorophyllides: Preparation, Purification, and Application. Biomolecules 2021; 11:biom11081115. [PMID: 34439782 PMCID: PMC8392590 DOI: 10.3390/biom11081115] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 07/20/2021] [Accepted: 07/20/2021] [Indexed: 12/18/2022] Open
Abstract
Chlorophyllides can be found in photosynthetic organisms. Generally, chlorophyllides have a-, b-, c-, d-, and f-type derivatives, and all chlorophyllides have a tetrapyrrole structure with a Mg ion at the center and a fifth isocyclic pentanone. Chlorophyllide a can be synthesized from protochlorophyllide a, divinyl chlorophyllide a, or chlorophyll. In addition, chlorophyllide a can be transformed into chlorophyllide b, chlorophyllide d, or chlorophyllide f. Chlorophyllide c can be synthesized from protochlorophyllide a or divinyl protochlorophyllide a. Chlorophyllides have been extensively used in food, medicine, and pharmaceutical applications. Furthermore, chlorophyllides exhibit many biological activities, such as anti-growth, antimicrobial, antiviral, antipathogenic, and antiproliferative activity. The photosensitivity of chlorophyllides that is applied in mercury electrodes and sensors were discussed. This article is the first detailed review dedicated specifically to chlorophyllides. Thus, this review aims to describe the definition of chlorophyllides, biosynthetic routes of chlorophyllides, purification of chlorophyllides, and applications of chlorophyllides.
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Affiliation(s)
- Yi-Ting Wang
- Department of Biological Science and Technology, I-Shou University, Kaohsiung 82445, Taiwan; (Y.-T.W.); (C.-H.Y.)
| | - Chih-Hui Yang
- Department of Biological Science and Technology, I-Shou University, Kaohsiung 82445, Taiwan; (Y.-T.W.); (C.-H.Y.)
- Pharmacy Department of E-Da Hospital, Kaohsiung 82445, Taiwan
- Taiwan Instrument Research Institute, National Applied Research Laboratories, Taipei 106214, Taiwan
| | - Keng-Shiang Huang
- The School of Chinese Medicine for Post-Baccalaureate, I-Shou University, Kaohsiung 82445, Taiwan
- Correspondence: (K.-S.H.); (J.-F.S.); Tel.: +886-7-6151100 (ext. 7063) (K.-S.H.); +886-7-6151100 (ext. 7310) (J.-F.S.); Fax: +886-7-6151959 (J.-F.S.)
| | - Jei-Fu Shaw
- Department of Biological Science and Technology, I-Shou University, Kaohsiung 82445, Taiwan; (Y.-T.W.); (C.-H.Y.)
- Correspondence: (K.-S.H.); (J.-F.S.); Tel.: +886-7-6151100 (ext. 7063) (K.-S.H.); +886-7-6151100 (ext. 7310) (J.-F.S.); Fax: +886-7-6151959 (J.-F.S.)
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Suehiro H, Tanaka R, Ito H. Distribution and functional analysis of the two types of 8-vinyl reductase involved in chlorophyll biosynthesis in marine cyanobacteria. Arch Microbiol 2021; 203:3565-3575. [PMID: 33956163 DOI: 10.1007/s00203-021-02348-w] [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: 03/23/2021] [Revised: 04/20/2021] [Accepted: 04/22/2021] [Indexed: 10/21/2022]
Abstract
In the chlorophyll biosynthesis pathway, the 8-vinyl group of the chlorophyll precursor is reduced to an ethyl group by 8-vinyl reductase. Two isozymes of 8-vinyl reductase have been described in oxygenic photosynthetic organisms: one encoded by BciA and another by BciB. Only BciB contains an [Fe-S] cluster and most cyanobacteria harbor this form; whereas a few contain BciA. Given this disparity in distribution, cyanobacterial BciA has remained largely overlooked, which has limited understanding of chlorophyll biosynthesis in these microorganisms. Here, we reveal that cyanobacterial BciA encodes a functional 8-vinyl reductase, as evidenced by measuring the in vitro activity of recombinant Synechococcus and Acaryochloris BciA. Genomic comparison revealed that BciB had been replaced by BciA during evolution of the marine cyanobacterium Synechococcus, and coincided with replacement of Fe-superoxide dismutase (SOD) with Ni-SOD. These findings imply that the acquisition of BciA confers an adaptive advantage to cyanobacteria living in low-iron oceanic environments.
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Affiliation(s)
- Haruka Suehiro
- Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan
| | - Ryouichi Tanaka
- Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan
| | - Hisashi Ito
- Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan.
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3
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Mg-protoporphyrin IX monomethyl ester cyclase from Rhodobacter capsulatus: radical SAM-dependent synthesis of the isocyclic ring of bacteriochlorophylls. Biochem J 2020; 477:4635-4654. [DOI: 10.1042/bcj20200761] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 11/16/2020] [Accepted: 11/19/2020] [Indexed: 11/17/2022]
Abstract
During bacteriochlorophyll a biosynthesis, the oxygen-independent conversion of Mg-protoporphyrin IX monomethyl ester (Mg-PME) to protochlorophyllide (Pchlide) is catalyzed by the anaerobic Mg-PME cyclase termed BchE. Bioinformatics analyses in combination with pigment studies of cobalamin-requiring Rhodobacter capsulatus mutants indicated an unusual radical S-adenosylmethionine (SAM) and cobalamin-dependent BchE catalysis. However, in vitro biosynthesis of the isocyclic ring moiety of bacteriochlorophyll using purified recombinant BchE has never been demonstrated. We established a spectroscopic in vitro activity assay which was subsequently validated by HPLC analyses and H218O isotope label transfer onto the carbonyl-group (C-131-oxo) of the isocyclic ring of Pchlide. The reaction product was further converted to chlorophyllide in the presence of light-dependent Pchlide reductase. BchE activity was stimulated by increasing concentrations of NADPH or SAM, and inhibited by S-adenosylhomocysteine. Subcellular fractionation experiments revealed that membrane-localized BchE requires an additional, heat-sensitive cytosolic component for activity. BchE catalysis was not sustained in chimeric experiments when a cytosolic extract from E. coli was used as a substitute. Size-fractionation of the soluble R. capsulatus fraction indicated that enzymatic activity relies on a specific component with an estimated molecular mass between 3 and 10 kDa. A structure guided site-directed mutagenesis approach was performed on the basis of a three-dimensional homology model of BchE. A newly established in vivo complementation assay was used to investigate 24 BchE mutant proteins. Potential ligands of the [4Fe-4S] cluster (Cys204, Cys208, Cys211), of SAM (Phe210, Glu308 and Lys320) and of the proposed cobalamin cofactor (Asp248, Glu249, Leu29, Thr71, Val97) were identified.
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Abstract
Modified tetrapyrroles are large macrocyclic compounds, consisting of diverse conjugation and metal chelation systems and imparting an array of colors to the biological structures that contain them. Tetrapyrroles represent some of the most complex small molecules synthesized by cells and are involved in many essential processes that are fundamental to life on Earth, including photosynthesis, respiration, and catalysis. These molecules are all derived from a common template through a series of enzyme-mediated transformations that alter the oxidation state of the macrocycle and also modify its size, its side-chain composition, and the nature of the centrally chelated metal ion. The different modified tetrapyrroles include chlorophylls, hemes, siroheme, corrins (including vitamin B12), coenzyme F430, heme d1, and bilins. After nearly a century of study, almost all of the more than 90 different enzymes that synthesize this family of compounds are now known, and expression of reconstructed operons in heterologous hosts has confirmed that most pathways are complete. Aside from the highly diverse nature of the chemical reactions catalyzed, an interesting aspect of comparative biochemistry is to see how different enzymes and even entire pathways have evolved to perform alternative chemical reactions to produce the same end products in the presence and absence of oxygen. Although there is still much to learn, our current understanding of tetrapyrrole biogenesis represents a remarkable biochemical milestone that is summarized in this review.
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Affiliation(s)
- Donald A Bryant
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717
| | - C Neil Hunter
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Martin J Warren
- School of Biosciences, University of Kent, Canterbury CT2 7NJ, United Kingdom
- Quadram Institute Bioscience, Norwich Research Park, Norwich NR4 7UQ, United Kingdom
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5
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Yamamoto H, Mizoguchi T, Tsukatani Y, Tamiaki H, Kurisu G, Fujita Y. Chlorophyllide a oxidoreductase Preferentially Catalyzes 8-Vinyl Reduction over B-Ring Reduction of 8-Vinyl Chlorophyllide a in the Late Steps of Bacteriochlorophyll Biosynthesis. Chembiochem 2020; 21:1760-1766. [PMID: 32180325 DOI: 10.1002/cbic.201900785] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 02/25/2020] [Indexed: 11/08/2022]
Abstract
Bacteriochlorophyll a (BChl) is an essential pigment for anoxygenic photosynthesis. In late steps of the BChl biosynthesis of Rhodobacter capsulatus, the C8 vinyl group and C7=C8 double bond of 8-vinyl chlorophyllide a (8 V-Chlide) are reduced by a C8 vinyl reductase (8VR), BciA, and a nitrogenase-like enzyme, chlorophyllide a oxidoreductase (COR), respectively, to produce 3-vinyl-bacteriochlorphyllide a. Recently, we discovered 8VR activity in COR. However, the kinetic parameters of the COR 8VR activity remain unknown, while those of the COR C7=C8 reductase activity and BciA have been reported. Here, we determined the kinetic parameters of COR 8VR activity by using 8 V-Chlide. The Km value for 8 V-Chlide was 1.4 μM, which is much lower than the 6.2 μM determined for the C7=C8 reduction of Chlide. The kinetic parameters of the dual activities of COR suggest that COR catalyzes the reduction of the C8 vinyl group of 8 V-Chlide preferentially over C7=C8 reduction when both substrates are supplied during BChl biosynthesis.
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Affiliation(s)
- Haruki Yamamoto
- Graduate School of Bioagricultural Sciences, Nagoya University Furo-cho, Chikusa-ku, Nagoya, 464-8601, Japan
| | - Tadashi Mizoguchi
- Graduate School of Life Sciences, Ritsumeikan University Kusatsu, Shiga, 525-8577, Japan
| | - Yusuke Tsukatani
- Institute for Extra-cutting-edge Science and Technology Avant-garde Research (X-star), Japan Agency for Marine-Earth Science and Technology (JAMSTEC) Yokosuka, Kanagawa, 237-0061, Japan
| | - Hitoshi Tamiaki
- Graduate School of Life Sciences, Ritsumeikan University Kusatsu, Shiga, 525-8577, Japan
| | - Genji Kurisu
- Institute for Protein Research, Osaka University Suita, Osaka, 565-0871, Japan
| | - Yuichi Fujita
- Graduate School of Bioagricultural Sciences, Nagoya University Furo-cho, Chikusa-ku, Nagoya, 464-8601, Japan
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6
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Lim H, Tanaka A, Tanaka R, Ito H. In Vitro Enzymatic Activity Assays Implicate the Existence of the Chlorophyll Cycle in Chlorophyll b-Containing Cyanobacteria. PLANT & CELL PHYSIOLOGY 2019; 60:2672-2683. [PMID: 31392311 DOI: 10.1093/pcp/pcz157] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 08/02/2019] [Indexed: 06/10/2023]
Abstract
In plants, chlorophyll (Chl) a and b are interconvertible by the action of three enzymes-chlorophyllide a oxygenase, Chl b reductase (CBR) and 7-hydroxymethyl chlorophyll a reductase (HCAR). These reactions are collectively referred to as the Chl cycle. In plants, this cyclic pathway ubiquitously exists and plays essential roles in acclimation to different light conditions at various developmental stages. By contrast, only a limited number of cyanobacteria species produce Chl b, and these include Prochlorococcus, Prochloron, Prochlorothrix and Acaryochloris. In this study, we investigated a possible existence of the Chl cycle in Chl b synthesizing cyanobacteria by testing in vitro enzymatic activities of CBR and HCAR homologs from Prochlorothrix hollandica and Acaryochloris RCC1774. All of these proteins show respective CBR and HCAR activity in vitro, indicating that both cyanobacteria possess the potential to complete the Chl cycle. It is also found that CBR and HCAR orthologs are distributed only in the Chl b-containing cyanobacteria that habitat shallow seas or freshwater, where light conditions change dynamically, whereas they are not found in Prochlorococcus species that usually habitat environments with fixed lighting. Taken together, our results implicate a possibility that the Chl cycle functions for light acclimation in Chl b-containing cyanobacteria.
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Affiliation(s)
- HyunSeok Lim
- Institute of Low Temperature Science, Hokkaido University, N19 W8, Sapporo, 060-0819 Japan
| | - Ayumi Tanaka
- Institute of Low Temperature Science, Hokkaido University, N19 W8, Sapporo, 060-0819 Japan
| | - Ryouichi Tanaka
- Institute of Low Temperature Science, Hokkaido University, N19 W8, Sapporo, 060-0819 Japan
| | - Hisashi Ito
- Institute of Low Temperature Science, Hokkaido University, N19 W8, Sapporo, 060-0819 Japan
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7
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Canniffe DP, Thweatt JL, Gomez Maqueo Chew A, Hunter CN, Bryant DA. A paralog of a bacteriochlorophyll biosynthesis enzyme catalyzes the formation of 1,2-dihydrocarotenoids in green sulfur bacteria. J Biol Chem 2018; 293:15233-15242. [PMID: 30126840 PMCID: PMC6166724 DOI: 10.1074/jbc.ra118.004672] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 08/17/2018] [Indexed: 12/03/2022] Open
Abstract
Chlorobaculum tepidum, a green sulfur bacterium, utilizes chlorobactene as its major carotenoid, and this organism also accumulates a reduced form of this monocyclic pigment, 1′,2′-dihydrochlorobactene. The protein catalyzing this reduction is the last unidentified enzyme in the biosynthetic pathways for all of the green sulfur bacterial pigments used for photosynthesis. The genome of C. tepidum contains two paralogous genes encoding members of the FixC family of flavoproteins: bchP, which has been shown to encode an enzyme of bacteriochlorophyll biosynthesis; and bchO, for which a function has not been assigned. Here we demonstrate that a bchO mutant is unable to synthesize 1′,2′-dihydrochlorobactene, and when bchO is heterologously expressed in a neurosporene-producing mutant of the purple bacterium, Rhodobacter sphaeroides, the encoded protein is able to catalyze the formation of 1,2-dihydroneurosporene, the major carotenoid of the only other organism reported to synthesize 1,2-dihydrocarotenoids, Blastochloris viridis. Identification of this enzyme completes the pathways for the synthesis of photosynthetic pigments in Chlorobiaceae, and accordingly and consistent with its role in carotenoid biosynthesis, we propose to rename the gene cruI. Notably, the absence of cruI in B. viridis indicates that a second 1,2-carotenoid reductase, which is structurally unrelated to CruI (BchO), must exist in nature. The evolution of this carotenoid reductase in green sulfur bacteria is discussed herein.
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Affiliation(s)
- Daniel P Canniffe
- From the Department of Molecular Biology & Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom, .,the Department of Biochemistry & Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, and
| | - Jennifer L Thweatt
- the Department of Biochemistry & Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, and
| | - Aline Gomez Maqueo Chew
- the Department of Biochemistry & Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, and
| | - C Neil Hunter
- From the Department of Molecular Biology & Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Donald A Bryant
- the Department of Biochemistry & Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, and .,the Department of Chemistry & Biochemistry, Montana State University, Bozeman, Montana 59717
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8
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Azai C, Kobayashi M, Mizoguchi T, Tamiaki H, Terauchi K, Tsukatani Y. Rapid C8-vinyl reduction of divinyl-chlorophyllide a by BciA from Rhodobacter capsulatus. J Photochem Photobiol A Chem 2018. [DOI: 10.1016/j.jphotochem.2017.09.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Yoneda A, Wittmann BJ, King JD, Blankenship RE, Dantas G. Transcriptomic analysis illuminates genes involved in chlorophyll synthesis after nitrogen starvation in Acaryochloris sp. CCMEE 5410. PHOTOSYNTHESIS RESEARCH 2016; 129:171-182. [PMID: 27276888 DOI: 10.1007/s11120-016-0279-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 05/19/2016] [Indexed: 06/06/2023]
Abstract
Acaryochloris species are a genus of cyanobacteria that utilize chlorophyll (chl) d as their primary chlorophyll molecule during oxygenic photosynthesis. Chl d allows Acaryochloris to harvest red-shifted light, which gives them the ability to live in filtered light environments that are depleted in visible light. Although genomes of multiple Acaryochloris species have been sequenced, their analysis has not revealed how chl d is synthesized. Here, we demonstrate that Acaryochloris sp. CCMEE 5410 cells undergo chlorosis by nitrogen depletion and exhibit robust regeneration of chl d by nitrogen repletion. We performed a time course RNA-Seq experiment to quantify global transcriptomic changes during chlorophyll recovery. We observed upregulation of numerous known chl biosynthesis genes and also identified an oxygenase gene with a similar transcriptional profile as these chl biosynthesis genes, suggesting its possible involvement in chl d biosynthesis. Moreover, our data suggest that multiple prochlorophyte chlorophyll-binding homologs are important during chlorophyll recovery, and light-independent chl synthesis genes are more dominant than the light-dependent gene at the transcription level. Transcriptomic characterization of this organism provides crucial clues toward mechanistic elucidation of chl d biosynthesis.
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Affiliation(s)
- Aki Yoneda
- Department of Pathology, Washington University in St. Louis School of Medicine, St. Louis, MO, USA
- Center for Genome Sciences and Systems Biology, Washington University in St. Louis School of Medicine, St. Louis, MO, USA
| | - Bruce J Wittmann
- Department of Biology, Washington University in St. Louis, St. Louis, MO, USA
- Photosynthetic Antenna Research Center (PARC), Washington University in St. Louis, St. Louis, MO, USA
| | - Jeremy D King
- Department of Biology, Washington University in St. Louis, St. Louis, MO, USA
- Photosynthetic Antenna Research Center (PARC), Washington University in St. Louis, St. Louis, MO, USA
| | - Robert E Blankenship
- Department of Biology, Washington University in St. Louis, St. Louis, MO, USA.
- Photosynthetic Antenna Research Center (PARC), Washington University in St. Louis, St. Louis, MO, USA.
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO, USA.
| | - Gautam Dantas
- Department of Pathology, Washington University in St. Louis School of Medicine, St. Louis, MO, USA.
- Center for Genome Sciences and Systems Biology, Washington University in St. Louis School of Medicine, St. Louis, MO, USA.
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA.
- Department of Molecular Microbiology, Washington University in St. Louis School of Medicine, St. Louis, MO, USA.
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Two Unrelated 8-Vinyl Reductases Ensure Production of Mature Chlorophylls in Acaryochloris marina. J Bacteriol 2016; 198:1393-400. [PMID: 26903415 PMCID: PMC4836224 DOI: 10.1128/jb.00925-15] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2015] [Accepted: 02/13/2016] [Indexed: 11/20/2022] Open
Abstract
The major photopigment of the cyanobacterium Acaryochloris marina is chlorophyll d, while its direct biosynthetic precursor, chlorophyll a, is also present in the cell. These pigments, along with the majority of chlorophylls utilized by oxygenic phototrophs, carry an ethyl group at the C-8 position of the molecule, having undergone reduction of a vinyl group during biosynthesis. Two unrelated classes of 8-vinyl reductase involved in the biosynthesis of chlorophylls are known to exist, BciA and BciB. The genome of Acaryochloris marina contains open reading frames (ORFs) encoding proteins displaying high sequence similarity to BciA or BciB, although they are annotated as genes involved in transcriptional control (nmrA) and methanogenesis (frhB), respectively. These genes were introduced into an 8-vinyl chlorophyll a-producing ΔbciB strain of Synechocystis sp. strain PCC 6803, and both were shown to restore synthesis of the pigment with an ethyl group at C-8, demonstrating their activities as 8-vinyl reductases. We propose that nmrA and frhB be reassigned as bciA and bciB, respectively; transcript and proteomic analysis of Acaryochloris marina reveal that both bciA and bciB are expressed and their encoded proteins are present in the cell, possibly in order to ensure that all synthesized chlorophyll pigment carries an ethyl group at C-8. Potential reasons for the presence of two 8-vinyl reductases in this strain, which is unique for cyanobacteria, are discussed. IMPORTANCE The cyanobacterium Acaryochloris marina is the best-studied phototrophic organism that uses chlorophyll d for photosynthesis. Unique among cyanobacteria sequenced to date, its genome contains ORFs encoding two unrelated enzymes that catalyze the reduction of the C-8 vinyl group of a precursor molecule to an ethyl group. Carrying a reduced C-8 group may be of particular importance to organisms containing chlorophyll d. Plant genomes also contain orthologs of both of these genes; thus, the bacterial progenitor of the chloroplast may also have contained both bciA and bciB.
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Wang X, Liu L. Crystal Structure and Catalytic Mechanism of 7-Hydroxymethyl Chlorophyll a Reductase. J Biol Chem 2016; 291:13349-59. [PMID: 27072131 DOI: 10.1074/jbc.m116.720342] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Indexed: 11/06/2022] Open
Abstract
7-Hydroxymethyl chlorophyll a reductase (HCAR) catalyzes the second half-reaction in chlorophyll b to chlorophyll a conversion. HCAR is required for the degradation of light-harvesting complexes and is necessary for efficient photosynthesis by balancing the chlorophyll a/b ratio. Reduction of the hydroxymethyl group uses redox cofactors [4Fe-4S] cluster and FAD to transfer electrons and is difficult because of the strong carbon-oxygen bond. Here, we report the crystal structure of Arabidopsis HCAR at 2.7-Å resolution and reveal that two [4Fe-4S]clusters and one FAD within a very short distance form a consecutive electron pathway to the substrate pocket. In vitro kinetic analysis confirms the ferredoxin-dependent electron transport chain, thus supporting a proton-activated electron transfer mechanism. HCAR resembles a partial reconstruction of an archaeal F420-reducing [NiFe] hydrogenase, which suggests a common mode of efficient proton-coupled electron transfer through conserved cofactor arrangements. Furthermore, the trimeric form of HCAR provides a biological clue of its interaction with light-harvesting complex II.
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Affiliation(s)
- Xiao Wang
- From the Key Laboratory of Photobiology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing 100093 and the University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lin Liu
- From the Key Laboratory of Photobiology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing 100093 and
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12
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Grouzdev DS, Kuznetsov BB, Keppen OI, Krasil’nikova EN, Lebedeva NV, Ivanovsky RN. Reconstruction of bacteriochlorophyll biosynthesis pathways in the filamentous anoxygenic phototrophic bacterium Oscillochloris trichoides DG-6 and evolution of anoxygenic phototrophs of the order Chloroflexales. Microbiology (Reading) 2015; 161:120-130. [DOI: 10.1099/mic.0.082313-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Denis S. Grouzdev
- Faculty of Biology, Moscow State University, Moscow, Russia
- Bioengineering Center, Russian Academy of Sciences, Moscow, Russia
| | | | - Olga I. Keppen
- Faculty of Biology, Moscow State University, Moscow, Russia
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13
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Elucidation of the preferred routes of C8-vinyl reduction in chlorophyll and bacteriochlorophyll biosynthesis. Biochem J 2014; 462:433-40. [PMID: 24942864 PMCID: PMC4214422 DOI: 10.1042/bj20140163] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Most of the chlorophylls and bacteriochlorophylls utilized for light harvesting by phototrophic organisms carry an ethyl group at the C8 position of the molecule, the product of a C8-vinyl reductase acting on a chlorophyll/bacteriochlorophyll biosynthetic precursor. Two unrelated classes of C8-vinyl reductase are known to exist, BciA and BciB, found in the purple phototroph Rhodobacter sphaeroides and the cyanobacterium Synechocystis sp. PCC6803 respectively. We constructed strains of each bacterium with the native C8-vinyl reductase swapped for the other class of the enzyme, and combined these replacements with a series of deletions of the native bch and chl genes. In vivo data indicate that the preferred substrates for both classes of the enzyme is C8-vinyl chlorophyllide, with C8-vinyl protochlorophyllide reduced only under conditions in which this pigment accumulates as a result of perturbed formation of chlorophyllide. The step in (bacterio)chlorophyll biosynthesis at which the vinyl group at the C8 position is reduced, forming an ethyl group, has been disputed. Results from species utilizing unrelated reductases suggest that C8-vinyl chlorophyllide is the preferred substrate for both enzymes.
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Harada J, Mizoguchi T, Tsukatani Y, Yokono M, Tanaka A, Tamiaki H. Chlorophyllide a oxidoreductase works as one of the divinyl reductases specifically involved in bacteriochlorophyll a biosynthesis. J Biol Chem 2014; 289:12716-26. [PMID: 24637023 DOI: 10.1074/jbc.m113.546739] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Bacteriochlorophyll a is widely distributed among anoxygenic photosynthetic bacteria. In bacteriochlorophyll a biosynthesis, the reduction of the C8 vinyl group in 8-vinyl-chlorophyllide a is catalyzed to produce chlorophyllide a by an 8-vinyl reductase called divinyl reductase (DVR), which has been classified into two types, BciA and BciB. However, previous studies demonstrated that mutants lacking the DVR still synthesize normal bacteriochlorophyll a with the C8 ethyl group and suggested the existence of an unknown "third" DVR. Meanwhile, we recently observed that chlorophyllide a oxidoreductase (COR) of a purple bacterium happened to show the 8-vinyl reduction of 8-vinyl-chlorophyllide a in vitro. In this study, we made a double mutant lacking BciA and COR of the purple bacterium Rhodobacter sphaeroides in order to investigate whether the mutant still produces pigments with the C8 ethyl group or if COR actually works as the third DVR. The single mutant deleting BciA or COR showed production of the C8 ethyl group pigments, whereas the double mutant accumulated 8-vinyl-chlorophyllide, indicating that there was no enzyme other than BciA and COR functioning as the unknown third DVR in Rhodobacter sphaeroides (note that this bacterium has no bciB gene). Moreover, some COR genes derived from other groups of anoxygenic photosynthetic bacteria were introduced into the double mutant, and all of the complementary strains produced normal bacteriochlorophyll a. This observation indicated that COR of these bacteria performs two functions, reductions of the C8 vinyl group and the C7=C8 double bond, and that such an activity is probably conserved in the widely ranging groups.
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Affiliation(s)
- Jiro Harada
- From the Department of Medical Biochemistry, Kurume University School of Medicine, Asahi-machi 67, Kurume, Fukuoka 830-0011, Japan
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Ito H, Tanaka A. Evolution of a new chlorophyll metabolic pathway driven by the dynamic changes in enzyme promiscuous activity. PLANT & CELL PHYSIOLOGY 2014; 55:593-603. [PMID: 24399236 DOI: 10.1093/pcp/pct203] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Organisms generate an enormous number of metabolites; however, the mechanisms by which a new metabolic pathway is acquired are unknown. To elucidate the importance of promiscuous enzyme activity for pathway evolution, the catalytic and substrate specificities of Chl biosynthetic enzymes were examined. In green plants, Chl a and Chl b are interconverted by the Chl cycle: Chl a is hydroxylated to 7-hydroxymethyl chlorophyll a followed by the conversion to Chl b, and both reactions are catalyzed by chlorophyllide a oxygenase. Chl b is reduced to 7-hydroxymethyl chlorophyll a by Chl b reductase and then converted to Chl a by 7-hydroxymethyl chlorophyll a reductase (HCAR). A phylogenetic analysis indicated that HCAR evolved from cyanobacterial 3,8-divinyl chlorophyllide reductase (DVR), which is responsible for the reduction of an 8-vinyl group in the Chl biosynthetic pathway. In addition to vinyl reductase activity, cyanobacterial DVR also has Chl b reductase and HCAR activities; consequently, three of the four reactions of the Chl cycle already existed in cyanobacteria, the progenitor of the chloroplast. During the evolution of cyanobacterial DVR to HCAR, the HCAR activity, a promiscuous reaction of cyanobacterial DVR, became the primary reaction. Moreover, the primary reaction (vinyl reductase activity) and some disadvantageous reactions were lost, but the neutral promiscuous reaction (NADH dehydrogenase) was retained in both DVR and HCAR. We also show that a portion of the Chl c biosynthetic pathway already existed in cyanobacteria. We discuss the importance of dynamic changes in promiscuous activity and of the latent pathways for metabolic evolution.
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Affiliation(s)
- Hisashi Ito
- Institute of Low Temperature Science, Hokkaido University, N19 W8, Kita-ku, Sapporo, 060-0819 Japan
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Tikh IB, Quin MB, Schmidt-Dannert C. A tale of two reductases: extending the bacteriochlorophyll biosynthetic pathway in E. coli. PLoS One 2014; 9:e89734. [PMID: 24586995 PMCID: PMC3931815 DOI: 10.1371/journal.pone.0089734] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 01/23/2014] [Indexed: 12/23/2022] Open
Abstract
The creation of a synthetic microbe that can harvest energy from sunlight to drive its metabolic processes is an attractive approach to the economically viable biosynthetic production of target compounds. Our aim is to design and engineer a genetically tractable non-photosynthetic microbe to produce light-harvesting molecules. Previously we created a modular, multienzyme system for the heterologous production of intermediates of the bacteriochlorophyll (BChl) pathway in E. coli. In this report we extend this pathway to include a substrate promiscuous 8-vinyl reductase that can accept multiple intermediates of BChl biosynthesis. We present an informative comparative analysis of homologues of 8-vinyl reductase from the model photosynthetic organisms Rhodobacter sphaeroides and Chlorobaculum tepidum. The first purification of the enzymes leads to their detailed biochemical and biophysical characterization. The data obtained reveal that the two 8-vinyl reductases are substrate promiscuous, capable of reducing the C8-vinyl group of Mg protoporphyrin IX, Mg protoporphyrin IX methylester, and divinyl protochlorophyllide. However, activity is dependent upon the presence of chelated Mg2+ in the porphyrin ring, with no activity against non-Mg2+ chelated intermediates observed. Additionally, CD analyses reveal that the two 8-vinyl reductases appear to bind the same substrate in a different fashion. Furthermore, we discover that the different rates of reaction of the two 8-vinyl reductases both in vitro, and in vivo as part of our engineered system, results in the suitability of only one of the homologues for our BChl pathway in E. coli. Our results offer the first insights into the different functionalities of homologous 8-vinyl reductases. This study also takes us one step closer to the creation of a nonphotosynthetic microbe that is capable of harvesting energy from sunlight for the biosynthesis of molecules of choice.
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Affiliation(s)
- Ilya B. Tikh
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, St. Paul, Minnesota, United States of America
| | - Maureen B. Quin
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, St. Paul, Minnesota, United States of America
| | - Claudia Schmidt-Dannert
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, St. Paul, Minnesota, United States of America
- * E-mail:
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Saunders AH, Golbeck JH, Bryant DA. Characterization of BciB: a ferredoxin-dependent 8-vinyl-protochlorophyllide reductase from the green sulfur bacterium Chloroherpeton thalassium. Biochemistry 2013; 52:8442-51. [PMID: 24151992 DOI: 10.1021/bi401172b] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Two enzymes, BciA and BciB, are known to reduce the C-8 vinyl group of 8-vinyl protochlorophyllide, producing protochlorophyllide a, during the synthesis of chlorophylls and bacteriochlorophylls in chlorophototrophic bacteria. BciA from the green sulfur bacterium Chlorobaculum tepidum reduces the C-8 vinyl group using NADPH as the reductant. Cyanobacteria and some other chlorophototrophs have a second, nonhomologous type of 8-vinyl reductase, BciB, but the biochemical properties of this enzyme have not yet been described. In this study, the bciB gene of the green sulfur bacterium Chloroherpeton thalassium was expressed in Escherichia coli , and the recombinant protein was purified and characterized. Recombinant BciB binds a flavin adenine dinucleotide cofactor, and EPR spectroscopy as well as quantitative analyses of bound iron and sulfide suggest that BciB binds two [4Fe-4S] clusters, one of which may not be essential for the activity of the enzyme. Using electrons provided by reduced ferredoxin or dithionite, recombinant BciB was active and reduced the 8-vinyl moiety of the substrate, 8-vinyl protochlorophyllide, producing protochlorophyllide a. A structural model for BciB based on a recent structure for the FrhB subunit of F420-reducing [NiFe]-hydrogenase of Methanothermobacter marburgensis is proposed. Possible reasons for the occurrence and distribution of BciA and BciB among various chlorophototrophs are discussed.
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Affiliation(s)
- Allison H Saunders
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
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Identification of an 8-vinyl reductase involved in bacteriochlorophyll biosynthesis in Rhodobacter sphaeroides and evidence for the existence of a third distinct class of the enzyme. Biochem J 2013; 450:397-405. [PMID: 23252506 DOI: 10.1042/bj20121723] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The purple phototrophic bacterium Rhodobacter sphaeroides utilises bacteriochlorophyll a for light harvesting and photochemistry. The synthesis of this photopigment includes the reduction of a vinyl group at the C8 position to an ethyl group, catalysed by a C8-vinyl reductase. An active form of this enzyme has not been identified in R. sphaeroides, but its genome contains two candidate ORFs (open reading frames) similar to those reported to encode C8-vinyl reductases in the closely related Rhodobacter capsulatus (bchJ), and in plants and green sulfur bacteria (rsp_3070). To determine which gene encodes the active enzyme, knock-out mutants in both genes were constructed. Surprisingly, mutants in which one or both genes were deleted still retained the ability to synthesize C8-ethyl bacteriochlorophyll. These genes were subsequently expressed in a cyanobacterial mutant that cannot synthesize C8-ethyl chlorophyll a. R. sphaeroides rsp_3070 was able to restore synthesis of the WT (wild-type) C8-ethyl chlorophyll a in the mutant, whereas bchJ did not. The results of the present study demonstrate that Rsp_3070 is a functional C8-vinyl reductase and that R. sphaeroides utilises at least two enzymes to catalyse this reaction, indicating the existence of a third class, while there remains no direct evidence for the activity of BchJ as a C8-vinyl reductase.
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An unexpectedly branched biosynthetic pathway for bacteriochlorophyll b capable of absorbing near-infrared light. Sci Rep 2013; 3:1217. [PMID: 23386973 PMCID: PMC3564038 DOI: 10.1038/srep01217] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Accepted: 01/18/2013] [Indexed: 01/30/2023] Open
Abstract
Chlorophyllous pigments are essential for photosynthesis. Bacteriochlorophyll (BChl) b has the characteristic C8-ethylidene group and therefore is the sole naturally occurring pigment having an absorption maximum at near-infrared light wavelength. Here we report that chlorophyllide a oxidoreductase (COR), a nitrogenase-like enzyme, showed distinct substrate recognition and catalytic reaction between BChl a- and b-producing proteobacteria. COR from BChl b-producing Blastochloris viridis synthesized the C8-ethylidene group from 8-vinyl-chlorophyllide a. In contrast, despite the highly conserved primary structures, COR from BChl a-producing Rhodobacter capsulatus catalyzes the C8-vinyl reduction as well as the previously known reaction of the C7 = C8 double bond reduction on 8-vinyl-chlorophyllide a. The present data indicate that the plasticity of the nitrogenase-like enzyme caused the branched pathways of BChls a and b biosynthesis, ultimately leading to ecologically different niches of BChl a- and b-based photosynthesis differentiated by more than 150 nm wavelength.
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Wang P, Wan C, Xu Z, Wang P, Wang W, Sun C, Ma X, Xiao Y, Zhu J, Gao X, Deng X. One divinyl reductase reduces the 8-vinyl groups in various intermediates of chlorophyll biosynthesis in a given higher plant species, but the isozyme differs between species. PLANT PHYSIOLOGY 2013; 161:521-34. [PMID: 23154534 PMCID: PMC3532282 DOI: 10.1104/pp.112.208421] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Divinyl reductase (DVR) converts 8-vinyl groups on various chlorophyll intermediates to ethyl groups, which is indispensable for chlorophyll biosynthesis. To date, five DVR activities have been detected, but adequate evidence of enzymatic assays using purified or recombinant DVR proteins has not been demonstrated, and it is unclear whether one or multiple enzymes catalyze these activities. In this study, we systematically carried out enzymatic assays using four recombinant DVR proteins and five divinyl substrates and then investigated the in vivo accumulation of various chlorophyll intermediates in rice (Oryza sativa), maize (Zea mays), and cucumber (Cucumis sativus). The results demonstrated that both rice and maize DVR proteins can convert all of the five divinyl substrates to corresponding monovinyl compounds, while both cucumber and Arabidopsis (Arabidopsis thaliana) DVR proteins can convert three of them. Meanwhile, the OsDVR (Os03g22780)-inactivated 824ys mutant of rice exclusively accumulated divinyl chlorophylls in its various organs during different developmental stages. Collectively, we conclude that a single DVR with broad substrate specificity is responsible for reducing the 8-vinyl groups of various chlorophyll intermediates in higher plants, but DVR proteins from different species have diverse and differing substrate preferences, although they are homologous.
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