scholarly journals Elucidation of the preferred routes of C8-vinyl reduction in chlorophyll and bacteriochlorophyll biosynthesis

2014 ◽  
Vol 462 (3) ◽  
pp. 433-440 ◽  
Author(s):  
Daniel P. Canniffe ◽  
Jack W. Chidgey ◽  
C. Neil Hunter
Keyword(s):  
Chlorophyll Biosynthesis ◽  
Ethyl Group ◽  
Vinyl Group ◽  
Bacteriochlorophyll Biosynthesis

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.

scholarly journals Two Unrelated 8-Vinyl Reductases Ensure Production of Mature Chlorophylls in Acaryochloris marina

2016 ◽  
Vol 198 (9) ◽  
pp. 1393-1400 ◽  
Author(s):  
Guangyu E. Chen ◽  
Andrew Hitchcock ◽  
Philip J. Jackson ◽  
Roy R. Chaudhuri ◽  
Mark J. Dickman ◽  
...  
Keyword(s):  
Transcriptional Control ◽  
Sequence Similarity ◽  
Open Reading Frames ◽  
High Sequence Similarity ◽  
Content Type ◽  
Ethyl Group ◽  
Acaryochloris Marina ◽  
Vinyl Group ◽  
Vinyl Reductase ◽  
Reading Frames

ABSTRACTThe major photopigment of the cyanobacteriumAcaryochloris marinais chlorophylld, while its direct biosynthetic precursor, chlorophylla, 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 ofAcaryochloris marinacontains 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 chlorophylla-producing ΔbciBstrain ofSynechocystissp. 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 thatnmrAandfrhBbe reassigned asbciAandbciB, respectively; transcript and proteomic analysis ofAcaryochloris marinareveal that bothbciAandbciBare 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.IMPORTANCEThe cyanobacteriumAcaryochloris marinais the best-studied phototrophic organism that uses chlorophylldfor 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 chlorophylld. Plant genomes also contain orthologs of both of these genes; thus, the bacterial progenitor of the chloroplast may also have contained bothbciAandbciB.

Chlorophyll a biosynthesis

1976 ◽  
Vol 273 (924) ◽  
pp. 207-225 ◽  
Keyword(s):  
Chlorophyll A ◽  
Chlorophyll Biosynthesis ◽  
Protoporphyrin Ix ◽  
Chlorophyll Synthesis ◽  
Synthesis Reaction ◽  
Etiolated Leaves ◽  
Regulatory Aspects ◽  
Vinyl Group ◽  
Chlorophyll A Biosynthesis ◽  
Monomethyl Ester

Protoporphyrin IX is believed to be an intermediate common to both haem and chlorophyll biosynthesis. The pathway specific to chlorophyll starts with magnesium protoporphyrin and its monomethyl ester. Two routes have been proposed for conversion of the latter compound to protochlorophyllide: A, formation of the isocyclic ring followed by reduction of the 4-vinyl group, or B, reduction of the 4-vinyl group followed by formation of the isocyclic ring. Membranes prepared from isolated barley etioplasts are found to convert magnesium 2,4-divinylphaeoporphyrin a 5 monomethyl ester to chlorophyllide a at a rate equal to that of chlorophyll synthesis in intact leaves: this result supports route A. NADPH is necessary to maintain the two successive reductive steps: reduction of the 4-vinyl group and then the photoreduction of ring IV to yield chlorophyllide. The prohaem content of etiolated leaves does not increase during the phase of active chlorophyll synthesis although evidence is presented that suggests that the ALA synthesis reaction that regulates chlorophyll synthesis is common to both pathways. This and other regulatory aspects are discussed.

Distribution and Functional Analysis of the Two Types of 8-vinyl Reductase Involved in Chlorophyll Biosynthesis in Marine Cyanobacteria

2021 ◽  
Author(s):  
Haruka Suehiro ◽  
Ryouichi Tanaka ◽  
Hisashi Ito
Keyword(s):  
Chlorophyll Biosynthesis ◽  
Marine Cyanobacteria ◽  
Biosynthesis Pathway ◽  
Genomic Comparison ◽  
Marine Cyanobacterium ◽  
Photosynthetic Organisms ◽  
Chlorophyll Precursor ◽  
Vinyl Group ◽  
Vinyl Reductase

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.

Cloning and Expression of Three Genes Involved in Chlorophyll Biosynthesis at Different Albescent Stages of Tea Plant Variety "Baiye 1"

2015 ◽  
Vol 41 (2) ◽  
pp. 240 ◽  
Author(s):  
Chun-Lei MA ◽  
Ming-Zhe YAO ◽  
Xin-Chao WANG ◽  
Ji-Qiang JIN ◽  
Jian-Qiang MA ◽  
...  
Keyword(s):  
Chlorophyll Biosynthesis ◽  
Tea Plant ◽  
Cloning And Expression ◽  
Plant Variety

scholarly journals Regulation of vitamin B12 and bacteriochlorophyll biosynthesis in a facultative methylotroph, Protaminobacter ruber.

1981 ◽  
Vol 27 (5) ◽  
pp. 439-447 ◽  
Author(s):  
Kazuyoshi SATO ◽  
Koichi ISHIDA ◽  
Teruyuki KUNG ◽  
Akihyro MIZUNO ◽  
Shoichi SHIMIZU
Keyword(s):  
Vitamin B12 ◽  
Facultative Methylotroph ◽  
Bacteriochlorophyll Biosynthesis

Structural basis of bilin binding by the chlorophyll biosynthesis regulator GUN4

2021 ◽  
Author(s):  
Jiu‐Hui Hu ◽  
Jing‐Wen Chang ◽  
Tao Xu ◽  
Jia Wang ◽  
Xiao Wang ◽  
...  
Keyword(s):  
Chlorophyll Biosynthesis ◽  
Structural Basis
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