Chlorophyll is synthesized from activated glutamate in the tetrapyrrole biosynthesis pathway through at least 20 different enzymatic reactions. Among these, the MgProto monomethylester (MgProtoME) cyclase catalyzes the formation of a fifth isocyclic ring to tetrapyrroles to form protochlorophyllide. The enzyme consists of two proteins. The CHL27 protein is proposed to be the catalytic component, while LCAA/YCF54 likely acts as a scaffolding factor. In comparison to other reactions of chlorophyll biosynthesis, this enzymatic step lacks clear elucidation and it is hardly understood, how electrons are delivered for the NADPH-dependent cyclization reaction. The present study intends to elucidate more precisely the role of LCAA/YCF54. Transgenic Arabidopsis lines with inactivated and overexpressed YCF54 reveal the mutual stability of YCF54 and CHL27. Among the YCF54-interacting proteins, the plastidal ferredoxin-NADPH reductase (FNR) was identified. We showed in N. tabacum and A. thaliana that a deficit of FNR1 or YCF54 caused MgProtoME accumulation, the substrate of the cyclase, and destabilization of the cyclase subunits. It is proposed that FNR serves as a potential donor for electrons required in the cyclase reaction and connects chlorophyll synthesis with photosynthetic activity.
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http://dx.doi.org/10.1111/tpj.13869 | DOI Listing |
Int J Mol Sci
May 2024
School of Biological Engineering, Dalian Polytechnic University, Dalian 116034, China.
Rice ( L.) is an important social-economic crop, and rice seedlings are easily affected by salt stress. Chitosan oligosaccharide (COS) plays a positive role in promoting plant growth and development.
View Article and Find Full Text PDFmBio
February 2023
BioTechnology Institute, University of Minnesota, St. Paul, Minnesota, USA.
Nitrogenase is the key enzyme involved in nitrogen fixation and uses low potential electrons delivered by ferredoxin (Fd) or flavodoxin (Fld) to reduce dinitrogen gas (N) to produce ammonia, generating hydrogen gas (H) as an obligate product of this activity. Although the phototrophic alphaproteobacterium Rhodopseudomonas palustris encodes multiple proteins that can reduce Fd, the FixABCX complex is the only one shown to support nitrogen fixation, and R. palustris Fix mutants grow poorly under nitrogen-fixing conditions.
View Article and Find Full Text PDFPlant J
May 2018
Humboldt-University Berlin, Life Sciences Faulty, Institute of Biology/Plant Physiology, Philippstraße 13, Building 12, 10115, Berlin, Germany.
Chlorophyll is synthesized from activated glutamate in the tetrapyrrole biosynthesis pathway through at least 20 different enzymatic reactions. Among these, the MgProto monomethylester (MgProtoME) cyclase catalyzes the formation of a fifth isocyclic ring to tetrapyrroles to form protochlorophyllide. The enzyme consists of two proteins.
View Article and Find Full Text PDFMol Microbiol
June 2017
Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA.
The sulfur response regulator, SurR, is among a handful of known redox-active transcriptional regulators. First characterized from the hyperthermophile Pyrococcus furiosus, it is unique to the archaeal order Thermococcales. P.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
March 2017
State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, China;
A large number of genes are necessary for the biosynthesis and activity of the enzyme nitrogenase to carry out the process of biological nitrogen fixation (BNF), which requires large amounts of ATP and reducing power. The multiplicity of the genes involved, the oxygen sensitivity of nitrogenase, plus the demand for energy and reducing power, are thought to be major obstacles to engineering BNF into cereal crops. Genes required for nitrogen fixation can be considered as three functional modules encoding electron-transport components (ETCs), proteins required for metal cluster biosynthesis, and the "core" nitrogenase apoenzyme, respectively.
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