The Allosteric Role of the AAA+ Domain of ChlD Protein from the Magnesium Chelatase of Synechocystis Species PCC 6803

Adams, Nathan B. P.; Reid, J. David

doi:10.1074/jbc.m113.477943

Cited by 19 publications

(36 citation statements)

References 22 publications

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“…9,12 In line with our previous work, no magnesium cooperativity was observed with the T. elongatus ChlD protein, even under the broader range of experimental conditions used here ( Figure S5). 12 The Synechocystis/T.…”

Section: −16supporting

confidence: 74%

“…12 This observation that the ChlD protein from Synechocystis is involved in magnesium cooperativity and the demonstration that the N-terminal AAA + nucleotide binding site allosterically controls chelatase activity lead to the view that the ChlD subunit acts as a regulatory hub for magnesium chelatase. 9,10 However, we do not know the basis for this control. The recent determination of the structure of the catalytic ChlH subunit 13 is an important step in understanding the structural basis for regulation and catalysis in magnesium chelatase mediated by ChlD.…”

Section: * S Supporting Informationmentioning

confidence: 99%

“…Our previous study demonstrated that the AAA + site present in the N-terminal domain of ChlD is an allosteric regulator of metal ion chelation, as mutants in this site affect both MgATP 2− and Mg 2+ binding. 9 Notably, these mutants also change the shape of the magnesium response curve; at the near saturating concentrations of MgATP 2− and porphyrin used, the wild-type Synechocystis enzyme showed a strongly sigmoidal response to free Mg 2+ with a Hill coefficient of 6.0 ± 0.3, while ChlD variants with mutations of the arginine finger (R208A) and in the Walker B motif (E152Q) are much less cooperative toward Mg 2+ with Hill coefficients of ∼2.5. We also described an R289A mutant with at least 10-fold poorer interaction with magnesium.…”

Section: −16mentioning

confidence: 99%

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Section: −16supporting

confidence: 74%

Section: * S Supporting Informationmentioning

confidence: 99%

Section: −16mentioning

confidence: 99%

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Spark plasma sintering of commercial and development titanium alloy powders

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“…This correlation argues for the requirement of proximity of the GUK and its protein substrate enabling rapid control of GUN4 by phosphorylation. Although ATP hydrolysis takes place during MgCh catalysis (Jensen et al, , 1998Adams and Reid, 2013), a phosphate transfer to GUN4 by the MgCh subunits H, D, and I was not observed in vitro (Supplemental Fig. S1).…”

Section: Gun4 Is Phosphorylated By a Plastid Membrane Localized Kinasementioning

confidence: 99%

Phosphorylation of GENOMES UNCOUPLED 4 Alters Stimulation of Mg Chelatase Activity in Angiosperms

et al. 2016

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) is a positive regulator of light-dependent chlorophyll biosynthesis. GUN4 activates Mg chelatase (MgCh) that catalyzes the insertion of an Mg 2+ ion into protoporphyrin IX. We show that Arabidopsis (Arabidopsis thaliana) GUN4 is phosphorylated at Ser 264 (S264), the penultimate amino acid residue at the C terminus. While GUN4 is preferentially phosphorylated in darkness, phosphorylation is reduced upon accumulation of Mg porphyrins. Expression of a phosphomimicking GUN4(S264D) results in an incomplete complementation of the white gun4-2 null mutant and a chlorotic phenotype comparable to gun4 knockdown mutants. Phosphorylated GUN4 has a reduced stimulatory effect on MgCh in vitro and in vivo but retains its protein stability and tetrapyrrole binding capacity. Analysis of GUN4 found in oxygenic photosynthetic organisms reveals the evolution of a C-terminal extension, which harbors the phosphorylation site of GUN4 expressed in angiosperms. Homologs of GUN4 from Synechocystis and Chlamydomonas lack the conserved phosphorylation site found in a C-terminal extension of angiosperm GUN4. Biochemical studies proved the importance of the C-terminal extension for MgCh stimulation and inactivation of GUN4 by phosphorylation in angiosperms. An additional mechanism regulating MgCh activity is proposed. In conjunction with the dark repression of 5-aminolevulinic acid synthesis, GUN4 phosphorylation minimizes the flow of intermediates into the Mg branch of the tetrapyrrole metabolic pathway for chlorophyll biosynthesis.

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“…Bioinformatic analysis suggested that there is a weak similarity between the MIDAS extension region and the D subunit of magnesium chelatases based upon the high density of basic and hydrophobic residues just upstream of the MIDAS domain (23). Magnesium chelatases, which play an important role in chlorophyll biosynthesis by inserting Mg 2ϩ into protoporphyrin, also contain C-terminal MIDAS domains and two N-terminal AAA domains (47). In addition to magnesium chelatases and midasin, there is only one other known protein, VWA8 (only found in higher organisms; function is unknown), that contains the combination of AAA and MIDAS domains (37).…”

Section: Discussionmentioning

confidence: 99%

The Crystal Structure of the Ubiquitin-like Domain of Ribosome Assembly Factor Ytm1 and Characterization of Its Interaction with the AAA-ATPase Midasin

Romes

Sobhany

Stanley

2016

Journal of Biological Chemistry

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The synthesis of eukaryotic ribosomes is a complex, energetically demanding process requiring the aid of numerous nonribosomal factors, such as the PeBoW complex. The mammalian PeBoW complex, composed of Pes1, Bop1, and WDR12, is essential for the processing of the 32S preribosomal RNA. Previous work in Saccharomyces cerevisiae has shown that release of the homologous proteins in this complex (Nop7, Erb1, and Ytm1, respectively) from preribosomal particles requires Rea1 (midasin or MDN1 in humans), a large dynein-like protein.Midasin contains a C-terminal metal ion-dependent adhesion site (MIDAS) domain that interacts with the N-terminal ubiquitin-like (UBL) domain of Ytm1/WDR12 as well as the UBL domain of Rsa4/Nle1 in a later step in the ribosome maturation pathway. Here we present the crystal structure of the UBL domain of the WDR12 homologue from S. cerevisiae at 1.7 Å resolution and demonstrate that human midasin binds to WDR12 as well as Nle1 through their respective UBL domains. Midasin contains a well conserved extension region upstream of the MIDAS domain required for binding WDR12 and Nle1, and the interaction is dependent upon metal ion coordination because removal of the metal or mutation of residues that coordinate the metal ion diminishes the interaction. Mammalian WDR12 displays prominent nucleolar localization that is dependent upon active ribosomal RNA transcription. Based upon these results, we propose that release of the PeBoW complex and subsequent release of Nle1 by midasin is a well conserved step in the ribosome maturation pathway in both yeast and mammalian cells.Ribosomes are large macromolecular machines composed of four pieces of ribosomal RNA (rRNA) 2 and 80 (79 in yeast) associated ribosomal proteins (1, 2). Ribosomes are responsible for carrying out the synthesis of all proteins within a cell, and the eukaryotic ribosome is composed of two subunits known as the small subunit (40S) and the large subunit (60S). The assembly of ribosomes begins in the nucleolus with the transcription of the rRNAs. Three of the rRNAs are transcribed as a single polycistronic precursor (18S, 5.8S, and 25S), which must then be modified, folded, processed, and exported to the cytoplasm in a carefully orchestrated manner (3, 4). Ribosome biogenesis in eukaryotic cells is an incredibly complex and energetically demanding process that requires more than 200 essential nonribosomal assembly factors (3-6). Defects in the mammalian ribosome biogenesis pathway are linked to a group of human diseases that are collectively called ribosomopathies. These are all congenital, inherited disorders with a broad clinical spectrum that have perplexed researchers for years because they cause tissue-specific effects although ribosomes are essential in all cell types (7). Ribosome biogenesis has also been emerging as a new target for cancer therapy. Recent studies have shown that several important oncogenes, including cMYC, RAS, and PI3K, play key roles in promoting hyperactive ribosome biogenesis, and deregulated ribosomal DNA...

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The Allosteric Role of the AAA+ Domain of ChlD Protein from the Magnesium Chelatase of Synechocystis Species PCC 6803

Cited by 19 publications

References 22 publications

Spark plasma sintering of commercial and development titanium alloy powders

Spark plasma sintering of commercial and development titanium alloy powders

Phosphorylation of GENOMES UNCOUPLED 4 Alters Stimulation of Mg Chelatase Activity in Angiosperms

The Crystal Structure of the Ubiquitin-like Domain of Ribosome Assembly Factor Ytm1 and Characterization of Its Interaction with the AAA-ATPase Midasin

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