The [4Fe4S] cluster of human DNA primase functions as a redox switch using DNA charge transport

O’Brien, Elizabeth; Holt, Marilyn; Thompson, Matthew K.; Salay, Lauren E.; Ehlinger, Aaron; Chazin, Walter; Barton, Jacqueline K.

doi:10.1126/science.aag1789

Cited by 130 publications

(223 citation statements)

References 55 publications

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“…(1) contains the I271S mutation and exhibits an anomalous structure at the DNA:RNA-binding interface that is drastically different from the conserved structure of human p58C and its yeast ortholog determined by two independent groups in four different protein assemblies (2–5) (Fig. 1A).…”

Section: Main Textmentioning

confidence: 85%

“…Without any explanation or qualification, O’Brien et al assumed that the β-hairpin structure in their mutated p58C binds the RNA:DNA substrate in the same way as the α-helical structure in wild-type (WT) p58C (see Figs. 3A, 3B, and S6 in (1)). Moreover, the authors concluded that Y345 and Y347, which are adjacent in the mutated p58C (Fig.…”

Section: Main Textmentioning

confidence: 99%

“…1D), which results in affinity for mutated p58C less than 1/150 that of the natural substrate for WT p58C (Kd=5.5 μM versus 33 nM; see Fig. S1 in (1) and Table 2 in (6), respectively). Previously Chazin’s group obtained a Kd of 0.3 μM (Table S2 in (7)) instead of 5.5 μM as reported in (1) using the same protein, substrate and experimental procedure (1).…”

Section: Main Textmentioning

confidence: 99%

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Comment on “The [4Fe4S] cluster of human DNA primase functions as a redox switch using DNA charge transport”

Baranovskiy

Babayeva

Zhang

et al. 2017

Science

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Section: Main Textmentioning

confidence: 85%

Section: Main Textmentioning

confidence: 99%

Section: Main Textmentioning

confidence: 99%

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Comment on “The [4Fe4S] cluster of human DNA primase functions as a redox switch using DNA charge transport”

Baranovskiy

Babayeva

Zhang

et al. 2017

Science

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“…The exact role of the Fe-S clusters in DNA metabolism proteins has been long debated. Interestingly, recent studies suggest that the redox state of Fe-S repair enzymes is crucial for their ability to find and repair DNA lesions (93). Prior to the most recent exciting investigations, it was postulated that the main role of the Fe-S clusters in DNA metabolism enzymes was to provide structural stability (94).…”

Section: How Are Fe-s Clusters Delivered To Correct Recipient Proteins?mentioning

confidence: 99%

Biogenesis and functions of mammalian iron-sulfur proteins in the regulation of iron homeostasis and pivotal metabolic pathways

Rouault

Maio

2017

Journal of Biological Chemistry

135

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Fe-S cofactors are composed of iron and inorganic sulfur in various stoichiometries. A complex assembly pathway conducts their initial synthesis and subsequent binding to recipient proteins. In this minireview, we discuss how discovery of the role of the mammalian cytosolic aconitase, known as iron regulatory protein 1 (IRP1), led to the characterization of the function of its Fe-S cluster in sensing and regulating cellular iron homeostasis. Moreover, we present an overview of recent studies that have provided insights into the mechanism of Fe-S cluster transfer to recipient Fe-S proteins. Discovery of a regulatory role for an iron-sulfur cluster in iron regulatory protein 1Interest in understanding how mammalian cells regulated iron uptake and distribution in the 1980s led to the discovery of a post-transcriptional regulatory mechanism, which was found to be crucial for cellular and systemic iron homeostasis in vertebrates. It was known that the expression of a major iron storage protein, ferritin (Ft), 2 was primarily regulated at the translational rather than transcriptional level (1, 2). However, it was not possible to dissect how ferritin levels were controlled under different conditions of iron availability until the genes encoding H and L ferritin were cloned in 1984 (2). At that time, gel-shift assays were commonly used to demonstrate direct binding of specific transcription factors to DNA sequences. A similar approach revealed that one or more cytosolic proteins were bound to the 5Ј-untranslated (5Ј-UTR) region of ferritin transcripts in mammalian cells (3-5). Moreover, it appeared that the binding factors reflected the iron status of the cell, as ferritin translation and gel-shift binding activity were reduced in cells that were iron-deficient, while conversely increasing in cells that were iron-loaded. The region of the ferritin transcripts responsible for mediating translational regulation was identified and subsequently named the IRE, for iron-responsive element. The IRE was defined through mutagenesis and sequence homology as a short stem-loop structure located near the 5Ј-end of the ferritin transcript. Intensive efforts to identify cytosolic factors that bound to the IRE resulted in cloning of two major cytosolic regulatory proteins, iron regulatory proteins 1 and 2 (IRP1 and IRP2) (5). It was immediately apparent, upon inspection of its primary amino acid sequence, that IRP1 was remarkably similar to mitochondrial aconitase, which was a well-characterized Fe-S protein. A cubane [Fe 4 -S 4 ] cluster in the IRP1 active-site cleft was known to be critical for the reversible aconitase-mediated conversion of citrate to isocitrate (6), which is essential for cholesterol and fatty acid metabolism, as citrate is the substrate of ATP-citrate lyase, which generates acetyl-coenzyme A utilized for cholesterol and lipid biosynthesis. Additionally, citrate has important regulatory roles in glycolysis and fatty acid synthesis and oxidation (7). Isocitrate is also metabolized by the cytosolic NADP-dependent iso...

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“…Moreover, a recent study revealed that DNA-mediated ET played an important role in primase functions. 5 To clarify chemical roles of ET in vivo, we need to study DNA-mediated ET under crowded conditions, because the intracellular environment is highly crowded with 2040 wt % various biomolecules. Crowding by biomolecules causes changes in structures and stabilities of DNA as well as enzymatic reactivities to DNA.…”

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confidence: 99%

Effects of Molecular-crowding on Electron Transfer and Oxidative Damage in Pyrene-modified Oligonucleotides

2018

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We examined guanine damages caused by photoinduced electron transfer (ET) in biomimetic environments using pyrenemodified oligonucleotides and molecular crowders. As a result, guanine damage induced by ET in full-matched DNA was decreased under viscous crowding conditions. On the other hand, behaviors of mismatched DNA revealed that throughspace ET between pyrene moiety and the consecutive guanine site was promoted under molecular-crowding conditions.Keywords: Guanine damage | DNA-mediated electron transfer | Molecular crowdingMechanisms of electron transfer (ET) through double helical DNA have been elucidated by extensive studies using electron donors and acceptors bound to DNA.1 It is well known that a hole injected by a photooxidant moves through base stacking and oxidizes DNA at a guanine (G) site, which is the most easily oxidized base. Oxidative damage within the genome is one of the important themes involving DNA-mediated ET.2 DNAmediated ET within the nucleosome structure has been examined by a rhodium intercalator 3 and an anthraquinone 4 as photooxidants. Moreover, a recent study revealed that DNA-mediated ET played an important role in primase functions.5 To clarify chemical roles of ET in vivo, we need to study DNA-mediated ET under crowded conditions, because the intracellular environment is highly crowded with 2040 wt % various biomolecules. Crowding by biomolecules causes changes in structures and stabilities of DNA as well as enzymatic reactivities to DNA. 6 Thus, DNA-mediated ET and DNA oxidative damages will also be affected by large amounts of coexisting molecules that change molecular diffusion rates, associations of molecules, solvent polarity, and water activity. Herein we investigated the effect of the surrounding medium on DNA damage via photoinduced ET using pyrene-modified oligonucleotides and found that molecular crowding mediums affected the efficiency of oxidative damage and the path of photoinduced ET in DNA.In this study, 5-(pyrenylethynyl)-2¤-deoxyuridine ( Py U) was used as a hole injector in DNA. The photoexcited Py U works as both hole and electron injectors for DNA-mediated ET.79 ET initiated by hole injection from the excited Py U can be evaluated by decomposition of guanines under air. It is advantageous for the study that the alkynylpyrene moiety of Py U is hardly quenched by oxygen and has long absorption wavelength. 10DNA sequences used in this investigation are shown in Figure 1. A pyrene molecule incorporated onto the 5-position of uracil via ethynyl linkage is located in DNA major groove, thus maintaining the the hydrogen bonding with adenine. 7 The DNA strands were designed to examine molecular-crowding effects on intrastrand ET in DNA. As DNA I, three adenines are embedded between Py U and GG. Continuous guanine (G) site 11 with the lowest oxidation potential is considered to trap a hole injected from the excited Py U via DNA-mediated ET and to generate guanine radical cation (G •+ ) at the GG site. Other guanines paired with C were replaced by inosines (inosine, I),...

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The [4Fe4S] cluster of human DNA primase functions as a redox switch using DNA charge transport

Cited by 130 publications

References 55 publications

Comment on “The [4Fe4S] cluster of human DNA primase functions as a redox switch using DNA charge transport”

Comment on “The [4Fe4S] cluster of human DNA primase functions as a redox switch using DNA charge transport”

Biogenesis and functions of mammalian iron-sulfur proteins in the regulation of iron homeostasis and pivotal metabolic pathways

Effects of Molecular-crowding on Electron Transfer and Oxidative Damage in Pyrene-modified Oligonucleotides

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