title: Five glutamic acid residues in the C-terminal domain of the ChlD subunit play a major role in conferring Mg(2+) cooperativity upon magnesium chelatase.
abstract: Magnesium chelatase catalyzes the first committed step in chlorophyll biosynthesis by inserting a Mg(2+) ion into protoporphyrin IX in an ATP-dependent manner. The cyanobacterial (Synechocystis) and higher-plant chelatases exhibit a complex cooperative response to free magnesium, while the chelatases from Thermosynechococcus elongatus and photosynthetic bacteria do not. To investigate the basis for this cooperativity, we constructed a series of chimeric ChlD proteins using N-terminal, central, and C-terminal domains from Synechocystis and Thermosynechococcus. We show that five glutamic acid residues in the C-terminal domain play a major role in this process.
authors.affiliation: Department of Molecular Biology and Biotechnology, The University of Sheffield , Sheffield S10 2TN, U.K.
authors.forename: Amanda A
authors.initials: AA
authors.lastname: Brindley
authors.affiliation: Department of Molecular Biology and Biotechnology, The University of Sheffield , Sheffield S10 2TN, U.K.
authors.forename: Nathan B P
authors.initials: NB
authors.lastname: Adams
authors.affiliation: Department of Molecular Biology and Biotechnology, The University of Sheffield , Sheffield S10 2TN, U.K.
authors.forename: C Neil
authors.initials: CN
authors.lastname: Hunter
authors.affiliation: Department of Chemistry, The University of Sheffield , Sheffield S3 7HF, U.K.
authors.forename: James D
authors.initials: JD
authors.lastname: Reid
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism*; D002413:Cations, Divalent / Q000378:metabolism; D018698:Glutamic Acid / Q000032:analysis / Q000378:metabolism; D008190:Lyases / Q000737:chemistry / Q000378:metabolism*; D008274:Magnesium / Q000378:metabolism*; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D046940:Synechococcus / Q000737:chemistry / Q000378:metabolism*; D046939:Synechocystis / Q000737:chemistry / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D002413:Cations, Divalent; D018698:Glutamic Acid; D008190:Lyases; C086788:magnesium chelatase; D008274:Magnesium