1
|
Hirose M, Tsukatani Y, Harada J, Tamiaki H. In vitro reversible dehydration in C3-substituents of zinc chlorophyll analogs by BchF and BchV enzymes: Stereoselectivity and substrate specificity in the dehydration. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2023; 1864:148959. [PMID: 36822492 DOI: 10.1016/j.bbabio.2023.148959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 02/14/2023] [Accepted: 02/15/2023] [Indexed: 02/25/2023]
Abstract
In the biosynthetic pathway of bacteriochlorophyll(BChl)-a/b/c/d/e molecules, BchF and BchV enzymes catalyze the hydration of a C3-vinyl to C3-1-hydroxyethyl group. In this study, the in vitro reactions catalyzed by BchF and BchV partially afforded a C31-epimeric mixture of the hydrated products (secondary alcohols), with the primary recovery of the C3-vinylated substrate. The stereoselectivity and substrate specificity for the in vitro reverse enzymatic dehydration were examined using zinc chlorophyll analogs as model substrates by BchF and BchV, which were obtained from extracts of Escherichia coli overexpressing the respective genes from Chlorobaculum tepidum and used without further purification. Both BchF and BchV preferred dehydration of the (31R)-epimers over the (31S)-epimers. The (31R)-epimer was directly dehydrated by BchF and BchV to give the C3-vinylated product. By contrast, two reaction pathways for BchF and BchV dehydrations of the (31S)-epimer were proposed: (1) the (31S)-epimer would be directly dehydrated to C3-vinyl group. (2) the (31S)-epimer would be epimerized to the (31R)-epimer, and the resulting epimer was dehydrated. The results indicated that both BchF and BchV did function as a hydratase/dehydratase and could play a role in the C31-epimerization. An increase in the alkyl size at the C8-position gradually suppressed the BchF and BchV-catalyzed dehydration in vitro, while the C121- and C20-methylation only slightly affected the reaction. Using the BchF dehydration, a large amount of 3-vinyl-bacteriochlorophyllide-a was successfully prepared, with the retention of the chemically labile, central magnesium atom.
Collapse
Affiliation(s)
- Mitsuaki Hirose
- 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), Kanagawa 237-0061, Japan
| | - Jiro Harada
- Department of Medical Biochemistry, Kurume University School of Medicine, Fukuoka 830-0011, Japan
| | - Hitoshi Tamiaki
- Graduate School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan.
| |
Collapse
|
2
|
Kim J, Kim C, Kim S, Ihee H, Shin W, Kim EJ, Lee JK. The Photoactive Photosynthetic Reaction Center of a Rhodobacter sphaeroides Mutant Lacking 3-Vinyl (Bacterio)Chlorophyllide a Hydratase Contains 3-Vinyl Bacteriochlorophyll a. Microbiol Spectr 2023; 11:e0387822. [PMID: 36971575 PMCID: PMC10101016 DOI: 10.1128/spectrum.03878-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 02/20/2023] [Indexed: 03/29/2023] Open
Abstract
Rhodobacter sphaeroides mutant BF-lacking 3-vinyl (bacterio)chlorophyllide a hydratase (BchF)-accumulates chlorophyllide a (Chlide a) and 3-vinyl bacteriochlorophyllide a (3V-Bchlide a). BF synthesizes 3-vinyl bacteriochlorophyll a (3V-Bchl a) through prenylation of 3V-Bchlide a and assembles a novel reaction center (V-RC) using 3V-Bchl a and Mg-free 3-vinyl bacteriopheophytin a (3V-Bpheo a) at a molar ratio of 2:1. We aimed to verify whether a bchF-deleted R. sphaeroides mutant produces a photochemically active RC that facilitates photoheterotrophic growth. The mutant grew photoheterotrophically-implying a functional V-RC-as confirmed by the emergence of growth-competent suppressors of bchC-deleted mutant (BC) under irradiation. Suppressor mutations in BC were localized to bchF, which diminished BchF activity and caused 3V-Bchlide a accumulation. bchF expression carrying the suppressor mutations in trans resulted in the coproduction of V-RC and wild-type RC (WT-RC) in BF. The V-RC had a time constant (τ) for electron transfer from the primary electron donor P (a dimer of 3V-Bchl a) to the A-side containing 3V-Bpheo a (HA) similar to that of the WT-RC and a 60% higher τ for electron transfer from HA to quinone A (QA). Thus, the electron transfer from HA to QA in the V-RC should be slower than that in the WT-RC. Furthermore, the midpoint redox potential of P/P+ of the V-RC was 33 mV more positive than that of the WT-RC. R. sphaeroides, thus, synthesizes the V-RC when 3V-Bchlide a accumulates. The V-RC can support photoheterotrophic growth; however, its photochemical activity is inferior to that of the WT-RC. IMPORTANCE 3V-Bchlide a is an intermediate in the bacteriochlorophyll a (Bchl a)-specific biosynthetic branch and prenylated by bacteriochlorophyll synthase. R. sphaeroides synthesizes V-RC that absorbs light at short wavelengths. The V-RC was not previously discovered because 3V-Bchlide a does not accumulate during the growth of WT cells synthesizing Bchl a. The levels of reactive oxygen species increased with the onset of photoheterotrophic growth in BF, resulting in a long lag period. Although the inhibitor of BchF is unknown, the V-RC may act as a substitute for the WT-RC when BchF is completely inhibited. Alternatively, it may act synergistically with WT-RC at low levels of BchF activity. The V-RC may broaden the absorption spectra of R. sphaeroides and supplement its photosynthetic ability at various wavelengths of visible light to a greater extent than that by the WT-RC alone.
Collapse
Affiliation(s)
- June Kim
- Department of Life Science, Sogang University, Seoul, Republic of Korea
| | - Changwon Kim
- Department of Chemistry and KI for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
- Center for Advanced Reaction Dynamics, Institute for Basic Science, Daejeon, Republic of Korea
| | - Siin Kim
- Department of Chemistry and KI for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
- Center for Advanced Reaction Dynamics, Institute for Basic Science, Daejeon, Republic of Korea
| | - Hyotcherl Ihee
- Department of Chemistry and KI for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
- Center for Advanced Reaction Dynamics, Institute for Basic Science, Daejeon, Republic of Korea
| | - Woonsup Shin
- Department of Chemistry, Sogang University, Seoul, Republic of Korea
| | - Eui-Jin Kim
- Microbial Research Department, Nakdonggang National Institute of Biological Resources, Gyeongsangbuk-do, Republic of Korea
| | - Jeong K. Lee
- Department of Life Science, Sogang University, Seoul, Republic of Korea
| |
Collapse
|
3
|
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.
Collapse
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
| |
Collapse
|
4
|
Hirose M, Teramura M, Harada J, Tamiaki H. BciC-Catalyzed C13 2 -Demethoxycarbonylation of Metal Pheophorbide a Alkyl Esters. Chembiochem 2020; 21:1473-1480. [PMID: 31900999 DOI: 10.1002/cbic.201900745] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Indexed: 11/10/2022]
Abstract
Bacteriochlorophyll c molecules self-aggregate to form large oligomers in the core part of chlorosomes, which are the main light-harvesting antenna systems of green photosynthetic bacteria. In the biosynthetic pathway of bacteriochlorophyll c, a BciC enzyme catalyzes the removal of the C132 -methoxycarbonyl group of chlorophyllide a, which possesses a free propionate residue at the C17-position and a magnesium ion as the central metal. The in vitro C132 -demethoxycarbonylations of chlorophyll a derivatives with various alkyl propionate residues and central metals were examined by using the BciC enzyme derived from one green sulfur bacteria species, Chlorobaculum tepidum. The BciC enzymatic reactions of zinc pheophorbide a alkyl esters were gradually suppressed with an increase of the alkyl chain length in the C17-propionate residue (from methyl to pentyl esters) and finally the hexyl ester became inactive for the BciC reaction. Although not only the zinc but also nickel and copper complexes were demethoxycarbonylated by the BciC enzyme, the reactions were largely dependent on the coordination ability of the central metals: Zn>Ni>Cu. The above substrate specificity indicates that the BciC enzyme would not bind directly to the carboxy group of chlorophyllide a, but would bind to its central magnesium to form the stereospecific complex of BciC with chlorophyllide a, giving pyrochlorophyllide a, which lacks the (132 R)-methoxycarbonyl group.
Collapse
Affiliation(s)
- Mitsuaki Hirose
- Graduated School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga, 525-8577, Japan
| | - Misato Teramura
- Graduated School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga, 525-8577, Japan
| | - Jiro Harada
- Medical Biochemistry, Kurume University School of Medicine, Kurume, Fukuoka, 830-0011, Japan
| | - Hitoshi Tamiaki
- Graduated School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga, 525-8577, Japan
| |
Collapse
|
5
|
Teramura M, Tsukatani Y, Harada J, Hirose M, Tamiaki H. Stereoselective C3‐substituent modification and substrate channeling by oxidoreductase BchC in bacteriochlorophyll
a
biosynthesis. FEBS Lett 2019; 593:799-809. [DOI: 10.1002/1873-3468.13372] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 03/12/2019] [Accepted: 03/14/2019] [Indexed: 11/10/2022]
Affiliation(s)
- Misato Teramura
- Graduate School of Life Sciences Ritsumeikan University Kusatsu Japan
| | - Yusuke Tsukatani
- Research and Development Center for Marine Biosciences Japan Agency for Marine‐Earth Science and Technology (JAMSTEC) Yokosuka Japan
| | - Jiro Harada
- Department of Medical Biochemistry Kurume University School of Medicine Japan
| | - Mitsuaki Hirose
- Graduate School of Life Sciences Ritsumeikan University Kusatsu Japan
| | - Hitoshi Tamiaki
- Graduate School of Life Sciences Ritsumeikan University Kusatsu Japan
| |
Collapse
|
6
|
Teramura M, Harada J, Tamiaki H. In vitro demethoxycarbonylation of various chlorophyll analogs by a BciC enzyme. PHOTOSYNTHESIS RESEARCH 2019; 139:163-171. [PMID: 30182280 DOI: 10.1007/s11120-018-0573-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 08/11/2018] [Indexed: 06/08/2023]
Abstract
Unique light-harvesting antennas in the green sulfur bacterium Chlorobaculum tepidum, called chlorosomes, consist of self-aggregates of bacteriochlorophyll (BChl) c. In the biosynthesis of BChl c, BciC demethoxycarbonylase removes the C132-methoxycarbonyl group to facilitate the self-aggregation of BChl c. We previously reported the in vitro BciC-enzymatic reactions and discussed the function of this enzyme in the biosynthesis of BChl c. This study aims to examine the substrate specificity of BciC in detail using several semi-synthetic (bacterio)chlorophyll derivatives. The results indicate that the substrate specificity of BciC is measurably affected by structural changes on the A/B rings including the bacteriochlorin π-systems. Moreover, BciC showed its activity on a Zn-chelated chlorophyll derivative. On the contrary, BciC recognized structural modifications on the D/E rings, including porphyrin pigments, which resulted in the significant decrease in the enzymatic activity. The utilization of BciC provides mild conditions that may be useful for the in vitro preparation of various chemically (un)stable chlorophyllous pigments.
Collapse
Affiliation(s)
- Misato Teramura
- Graduate School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga, 525-8577, Japan
| | - Jiro Harada
- Department of Medical Biochemistry, Kurume University School of Medicine, Kurume, Fukuoka, 830-0011, Japan
| | - Hitoshi Tamiaki
- Graduate School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga, 525-8577, Japan.
| |
Collapse
|
7
|
Teramura M, Tamiaki H. Semi-synthesis and HPLC analysis of (bacterio)chlorophyllides possessing a propionic acid residue at the C17-position. J PORPHYR PHTHALOCYA 2018. [DOI: 10.1142/s1088424618500347] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Various chlorophyll and bacteriochlorophyll derivatives possessing a magnesium or zinc atom at the central position and a free carboxylic acid group at the C17[Formula: see text]-position, also known as (bacterio)chlorophyllides, were synthesized through a combination of organic synthesis techniques and enzymatic steps. The semi-synthetic (bacterio)chlorophyllides were purified and analyzed using reversed-phase high-performance liquid chromatography with UV-vis spectroscopy and mass spectrometry. These free propionic acid-containing chlorophyllous pigments can be useful research materials for the study of (bacterio)chlorophyll metabolisms.
Collapse
Affiliation(s)
- Misato Teramura
- Graduate School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
| | - Hitoshi Tamiaki
- Graduate School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
| |
Collapse
|
8
|
Thweatt JL, Ferlez BH, Golbeck JH, Bryant DA. BciD Is a Radical S-Adenosyl-l-methionine (SAM) Enzyme That Completes Bacteriochlorophyllide e Biosynthesis by Oxidizing a Methyl Group into a Formyl Group at C-7. J Biol Chem 2016; 292:1361-1373. [PMID: 27994052 DOI: 10.1074/jbc.m116.767665] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Revised: 12/12/2016] [Indexed: 01/05/2023] Open
Abstract
Green bacteria are chlorophotorophs that synthesize bacteriochlorophyll (BChl) c, d, or e, which assemble into supramolecular, nanotubular structures in large light-harvesting structures called chlorosomes. The biosynthetic pathways of these chlorophylls are known except for one reaction. Null mutants of bciD, which encodes a putative radical S-adenosyl-l-methionine (SAM) protein, are unable to synthesize BChl e but accumulate BChl c; however, it is unknown whether BciD is sufficient to convert BChl c (or its precursor, bacteriochlorophyllide (BChlide) c) into BChl e (or BChlide e). To determine the function of BciD, we expressed the bciD gene of Chlorobaculum limnaeum strain DSMZ 1677T in Escherichia coli and purified the enzyme under anoxic conditions. Electron paramagnetic resonance spectroscopy of BciD indicated that it contains a single [4Fe-4S] cluster. In assays containing SAM, BChlide c or d, and sodium dithionite, BciD catalyzed the conversion of SAM into 5'-deoxyadenosine and BChlide c or d into BChlide e or f, respectively. Our analyses also identified intermediates that are proposed to be 71-OH-BChlide c and d Thus, BciD is a radical SAM enzyme that converts the methyl group of BChlide c or d into the formyl group of BChlide e or f This probably occurs by a mechanism involving consecutive hydroxylation reactions of the C-7 methyl group to form a geminal diol intermediate, which spontaneously dehydrates to produce the final products, BChlide e or BChlide f The demonstration that BciD is sufficient to catalyze the conversion of BChlide c into BChlide e completes the biosynthetic pathways for all "Chlorobium chlorophylls."
Collapse
Affiliation(s)
| | - Bryan H Ferlez
- From the Departments of Biochemistry and Molecular Biology and
| | - John H Golbeck
- From the Departments of Biochemistry and Molecular Biology and.,Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802 and
| | - Donald A Bryant
- From the Departments of Biochemistry and Molecular Biology and .,the Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717
| |
Collapse
|
9
|
Matsubara S, Kunieda M, Wada A, Sasaki SI, Tamiaki H. Visible and near-infrared spectra of chlorosomal zinc chlorin self-aggregates dependent on their peripheral substituents at the 8-position. J Photochem Photobiol A Chem 2016. [DOI: 10.1016/j.jphotochem.2016.07.028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
10
|
Teramura M, Harada J, Mizoguchi T, Yamamoto K, Tamiaki H. In Vitro Assays of BciC Showing C132-Demethoxycarbonylase Activity Requisite for Biosynthesis of Chlorosomal Chlorophyll Pigments. PLANT & CELL PHYSIOLOGY 2016; 57:1048-1057. [PMID: 26936794 DOI: 10.1093/pcp/pcw045] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 02/24/2016] [Indexed: 06/05/2023]
Abstract
A BciC enzyme is related to the removal of the C13(2)-methoxycarbonyl group in biosynthesis of bacteriochlorophylls (BChls) c, d and e functioning in green sulfur bacteria, filamentous anoxygenic phototrophs and phototrophic acidobacteria. These photosynthetic bacteria have the largest and the most efficient light-harvesting antenna systems, called chlorosomes, containing unique self-aggregates of BChl c, d or e pigments, that lack the C13(2)-methoxycarbonyl group which disturbs chlorosomal self-aggregation. In this study, we characterized the BciC derived from the green sulfur bacterium Chlorobaculum tepidum, and examined the in vitro enzymatic activities of its recombinant protein. The BciC-catalyzing reactions of various substrates showed that the enzyme recognized chlorophyllide (Chlide) a and 3,8-divinyl(DV)-Chlide a as chlorin substrates to give 3-vinyl-bacteriochlorophyllide (3V-BChlide) d and DV-BChlide d, respectively. Since the BciC afforded a higher activity with Chlide a than that with DV-Chlide a and no activity with (DV-)protoChlides a (porphyrin substrates) and 3V-BChlide a (a bacteriochlorin substrate), this enzyme was effective for diverting the chlorosomal pigment biosynthetic pathway at the stage of Chlide a away from syntheses of other pigments such as BChl a and Chl a The addition of methanol to the reaction mixture did not prevent the BciC activity, and we identified this enzyme as Chlide a demethoxycarbonylase, not methylesterase.
Collapse
Affiliation(s)
- Misato Teramura
- Graduate School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga, 525-8577 Japan
| | - Jiro Harada
- Department of Medical Biochemistry, Kurume University School of Medicine, Kurume, Fukuoka, 830-0011 Japan
| | - Tadashi Mizoguchi
- Graduate School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga, 525-8577 Japan
| | - Ken Yamamoto
- Department of Medical Biochemistry, Kurume University School of Medicine, Kurume, Fukuoka, 830-0011 Japan
| | - Hitoshi Tamiaki
- Graduate School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga, 525-8577 Japan
| |
Collapse
|