Mithramycin forms a stable dimeric complex by chelating with Fe(II): DNA-interacting characteristics, cellular permeation and cytotoxicity

Hou, Ming-Hon; Wang, Andrew H.‐J.

doi:10.1093/nar/gki276

Cited by 32 publications

(38 citation statements)

References 40 publications

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“…DNase activity was determined by using an assay described previously (37), with minor modifications. Plasmid DNA (pGEX5T-1) was purified and used as the DNA substrate.…”

Section: Detection Of Cell Apoptosis (Annexin V)mentioning

confidence: 99%

White spot syndrome virus protein ICP11: A histone-binding DNA mimic that disrupts nucleosome assembly

Wang

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

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White spot syndrome virus (WSSV) is a large (Ϸ300 kbp), doublestranded DNA eukaryotic virus that has caused serious disease in crustaceans worldwide. ICP11 is the most highly expressed WSSV nonstructural gene/protein, which strongly suggests its importance in WSSV infection; but until now, its function has remained obscure. We show here that ICP11 acts as a DNA mimic. In crystal, ICP11 formed a polymer of dimers with 2 rows of negatively charged spots that approximated the duplex arrangement of the phosphate groups in DNA. Functionally, ICP11 prevented DNA from binding to histone proteins H2A, H2B, H3, and H2A.x, and in hemocytes from WSSVinfected shrimp, ICP11 colocalized with histone H3 and activated-H2A.x. These observations together suggest that ICP11 might interfere with nucleosome assembly and prevent H2A.x from fulfilling its critical function of repairing DNA double strand breaks. Therefore, ICP11 possesses a functionality that is unique among the handful of presently known DNA mimic proteins.apoptosis ͉ DNase enhancer ͉ crystal structure ͉ shrimp aquaculture T he white spot syndrome virus (WSSV) is an enveloped DNA virus that infects crustaceans and threatens shrimp aquaculture (1-4). The white spot disease caused by WSSV can result in 100% cumulative mortality in farmed shrimps in 2-10 days. Based on studies of individual genes and analysis of the complete genome sequence, the ellipsoid-shaped WSSV has been erected as the type species of a new genus (Whispovirus) of a new virus family Nimaviridae (5). Because of the large size of the viral genome (Ϸ300 kb) and the uniqueness of the encoded proteins, WSSV has not yet been fully characterized.In previous studies, both transcriptomic (WSSV-infected EST database and WSSV DNA microarray) and proteomic (2D electrophoresis) approaches identified ICP11 as a highly expressed WSSV gene/protein (6, 7). The high expression levels of this protein strongly suggest its importance to WSSV infection; but until now, its function has remained unknown. In the present article, we determine the crystal structure of ICP11 and use Far Western assays and indirect immunofluorescence to investigate its function and the factors with which it interacts. We found that ICP11 acts as a DNA mimic that prevents DNA from binding to histone proteins and, thus, disrupts nucleosome assembly. Results ICP11 CrystalStructure. The protein model of ICP11 was built manually into a clear electron density map [supporting information (SI) Fig. S1 A] derived from MAD X-ray diffraction data. The refined structure contains 2 ICP11 molecules as a dimer per asymmetric unit (Fig. 1). The refinement statistics are listed in Table S1. Each monomer consists of a 4-stranded anti-parallel ␤-sheet, a 2-stranded ␤-ribbon, and 2 flanking ␣-helices ( Fig. 1 A and B). In the center of the monomer, 16-aa side chains are associated into a hydrophobic core. Every secondary structural element contributes to this core structure; thus, forming a stable compact globular fold. The nature of the dimer interface is largely...

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“…DNase activity was determined by using an assay described previously (37), with minor modifications. Plasmid DNA (pGEX5T-1) was purified and used as the DNA substrate.…”

Section: Detection Of Cell Apoptosis (Annexin V)mentioning

confidence: 99%

White spot syndrome virus protein ICP11: A histone-binding DNA mimic that disrupts nucleosome assembly

Wang

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

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“…However, the exact role of metal ion coordination in the mechanism of action of UK-1 and analogs remains to be determined. There is a growing interest in the role of metal ions and their complexes in drug design [11][12][13][14], particularly in metal complex-DNA interactions [15][16][17][18][19][20][21]. Studies of UK-1 and its analogs may offer important insights, provided by nature, into how metal ion complexation can be harnessed in the design of selective cytotoxins.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, metal ion binding, and biological evaluation of new anticancer 2-(2′-hydroxyphenyl)benzoxazole analogs of UK-1

McKee¹,

Kerwin²

2008

Bioorganic & Medicinal Chemistry

165

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UK-1 is a bis(benzoxazole) natural product displaying activity against a wide range of human cancer cell lines. A simplified analog of UK-1, 4-carbomethoxy-2-(2'-hydroxyphenyl)benzoxazole, was previously found to be almost as active as UK-1 against cancer cell lines, and similar to the natural product, formed complexes with variety of metal ions such as Mg 2+ and Zn 2+ . A series 4-substituted-2-(2'-hydroxyphenyl)benzoxazole analogs of this "minimal pharmacophore" of UK-1 were prepared. The anti-cancer activity of these analogs was examined in breast and lung cancer cell lines. Spectrophotometric titrations in methanol were carried out in order to assess the ability of UK-1 and these analogs to coordinate with Mg 2+ and Cu 2+ ions. Although none of the new analogs were more cytotoxic than 4-carbomethoxy-2-(2'-hydroxyphenyl)benzoxazole, some analogs were identified that display similar cytotoxicity to this simplified UK-1 analog with improved water solubility. UK-1 and all of these new analogs bind Cu 2+ ions better than Mg 2+ ions, and the nature of the 4-substituent is important for the Mg 2+ ion binding ability of these 2-(2'-hydroxyphenyl) benzoxazoles. Previous studies of a limited number of UK-1 analogs demonstrated a correlation between Mg 2+ ion binding ability and cytotoxicity; however, within this series of 4-substituted-2-(2'-hydroxyphenyl)benzoxazoles the variations in cytotoxicity do not correlate with either Mg 2+ or Cu 2+ ion binding ability. These results, together with recent ESI-MS studies of Cu 2+ -mediated DNA binding by UK-1 and analogs, indicate that UK-1 and analogs may exert their cytotoxic effects by interaction with Cu 2+ or other transition metal ions, rather than Mg 2+ , and that metal ion-mediated DNA binding, rather than metal ion binding affinity, is important for the cytotoxic effect of these compounds. The potential role of Cu 2+ ions in the cytotoxic action of UK-1 is further supported by observation that UK-1 in the presence of Cu 2+ displays enhanced cytotoxicity to MCF-7 and A549 cells when compared to UK-1 alone.

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“…All spectra are represented as the average of three runs. The methods used for the CD spectral analysis have been described previously [30].…”

Section: Methodsmentioning

confidence: 99%

The impact of spermine competition on the efficacy of DNA-binding Fe(II), Co(II), and Cu(II) complexes of dimeric chromomycin A3

Wang

Yuann

et al. 2009

Journal of Inorganic Biochemistry

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Mithramycin forms a stable dimeric complex by chelating with Fe(II): DNA-interacting characteristics, cellular permeation and cytotoxicity

Cited by 32 publications

References 40 publications

White spot syndrome virus protein ICP11: A histone-binding DNA mimic that disrupts nucleosome assembly

White spot syndrome virus protein ICP11: A histone-binding DNA mimic that disrupts nucleosome assembly

Synthesis, metal ion binding, and biological evaluation of new anticancer 2-(2′-hydroxyphenyl)benzoxazole analogs of UK-1

The impact of spermine competition on the efficacy of DNA-binding Fe(II), Co(II), and Cu(II) complexes of dimeric chromomycin A3

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