Humboldt-Universität zu Berlin - AG Pflanzenphysiologie

Control of Chlorophyll Biosynthesis

Andreas Richter, Josephine Herbst, Peng Wang, Daniel Wittmann, Pawel Brzezowski, Maxi Rothbart


Starting from a common precursor, 5-aminolevulinic acid, the macro-cyclic porphyrin molecules are synthesized through a series of complex biochemical reactions. Then, at the branch point of tetrapyrrole biosynthesis, the pathway divides into the so called ‘iron-‘ and ‘magnesium-branch’. A metabolic intermediate protoporphyrin IX is either directed into the iron-branch for the synthesis of heme or into the Mg branch to form Mg-porphyrins and ultimately chlorophyll. In either case a metal chelatase – ferrochelatase for Fe2+ insertion (heme) or Mg chelatase for Mg2+ insertion (chlorophyll) - catalyzes the insertion of the metal ion into the porphyrin backbone.

During the last decades of intensive research on plant tetrapyrrole biosynthesis a remarkable amount of post-translational regulation mechanism where identified. Several evidences emerge that especially thiol-switches (redox-regulation) and phosphorylation of proteins contribute to the complex network of post-translational mechanisms balancing/ regulating chlorophyll biosynthesis.


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