scholarly journals The Binding Orientation of a Norindenoisoquinoline in the Topoisomerase I−DNA Cleavage Complex Is Primarily Governed by π−π Stacking Interactions

2008 ◽  
Vol 112 (31) ◽  
pp. 9484-9489 ◽  
Author(s):  
Yunlong Song ◽  
Mark Cushman
Keyword(s):  
Dna Cleavage ◽  
Topoisomerase I ◽  
Stacking Interactions ◽  
Π Stacking ◽  
Cleavage Complex ◽  
Binding Orientation

scholarly journals Antisense transcripts enhanced by camptothecin at divergent CpG-island promoters associated with bursts of topoisomerase I-DNA cleavage complex and R-loop formation

2013 ◽  
Vol 41 (22) ◽  
pp. 10110-10123 ◽  
Author(s):  
Jessica Marinello ◽  
Giovanni Chillemi ◽  
Susana Bueno ◽  
Stefano G. Manzo ◽  
Giovanni Capranico
Keyword(s):  
Dna Cleavage ◽  
Topoisomerase I ◽  
Cpg Island ◽  
Loop Formation ◽  
Antisense Transcripts ◽  
Cleavage Complex

scholarly journals DNA Topoisomerase I Inhibitory Activity of Quinochalcone C-glycosides from the Florets of Carthamus tinctorius

2017 ◽  
Vol 12 (11) ◽  
pp. 1934578X1701201
Author(s):  
Shi-Jun Yue ◽  
Wen-Xiao Wang ◽  
Cheng Qu ◽  
Lan-Ting Xin ◽  
Yu-Ping Tang ◽  
...  
Keyword(s):  
Inhibitory Activity ◽  
Dna Cleavage ◽  
Topoisomerase I ◽  
Docking Study ◽  
Carthamus Tinctorius ◽  
In Vitro Cytotoxicity ◽  
Molecular Docking Study ◽  
Dna Topoisomerase ◽  
Cleavage Complex

The DNA topoisomerase (Topo) I inhibitory activity of six quinochalcone C-glycosides (QCGs) isolated from the florets of Carthamus tinctorius were evaluated in vitro. Among them, anhydrosafflor yellow B (AHSYB, 4) and carthorquinoside B (6) could inhibit DNA Topo I at concentrations as low as 100 μM. Molecular docking study revealed that both of them have the capacity to stabilize Topo I-DNA cleavage complex in silico interacting with the essential binding sites, such as Arg364, Thr718 and TGP11. Besides, both compounds 4 and 6 exhibited no antitumor activity by in vitro cytotoxicity assays.

scholarly journals Analysis of RuvABC and RecG Involvement in the Escherichia coli Response to the Covalent Topoisomerase-DNA Complex

2010 ◽  
Vol 192 (17) ◽  
pp. 4445-4451 ◽  
Author(s):  
Jeanette H. Sutherland ◽  
Yuk-Ching Tse-Dinh
Keyword(s):  
Escherichia Coli ◽  
Homologous Recombination ◽  
Dna Cleavage ◽  
Topoisomerase I ◽  
Replication Fork ◽  
Double Strand Breaks ◽  
Strand Breaks ◽  
Sos Induction ◽  
Cleavage Complex ◽  
Dna Complex

ABSTRACT Topoisomerases form a covalent enzyme-DNA intermediate after initial DNA cleavage. Trapping of the cleavage complex formed by type IIA topoisomerases initiates the bactericidal action of fluoroquinolones. It should be possible also to identify novel antibacterial lead compounds that act with a similar mechanism on type IA bacterial topoisomerases. The cellular response and repair pathways for trapped topoisomerase complexes remain to be fully elucidated. The RuvAB and RecG proteins could play a role in the conversion of the initial protein-DNA complex to double-strand breaks and also in the resolution of the Holliday junction during homologous recombination. Escherichia coli strains with ruvA and recG mutations are found to have increased sensitivity to low levels of norfloxacin treatment, but the mutations had more pronounced effects on survival following the accumulation of covalent complexes formed by mutant topoisomerase I defective in DNA religation. Covalent topoisomerase I and DNA gyrase complexes are converted into double-strand breaks for SOS induction by the RecBCD pathway. SOS induction following topoisomerase I complex accumulation is significantly lower in the ruvA and recG mutants than in the wild-type background, suggesting that RuvAB and RecG may play a role in converting the initial single-strand DNA-protein cleavage complex into a double-strand break prior to repair by homologous recombination. The use of a ruvB mutant proficient in homologous recombination but not in replication fork reversal demonstrated that the replication fork reversal function of RuvAB is required for SOS induction by the covalent complex formed by topoisomerase I.

Self-Recognizing π-π Stacking Interactions Designed for the Generation of Ultrastable Mesoporous Hydrogen-Bonded Organic Frameworks

2019 ◽  
Author(s):  
KAIKAI MA ◽  
Peng Li ◽  
John Xin ◽  
Yongwei Chen ◽  
Zhijie Chen ◽  
...  
Keyword(s):  
Pore Size ◽  
Fiber Composite ◽  
Aqueous Media ◽  
Stacking Interactions ◽  
Mustard Gas ◽  
X Ray Diffraction ◽  
X Ray ◽  
Expansion Strategy ◽  
Π Stacking ◽  
Hydrogen Bonded

Creating crystalline porous materials with large pores is typically challenging due to undesired interpen-etration, staggered stacking, or weakened framework stability. Here, we report a pore size expansion strategy by self-recognizing π-π stacking interactions in a series of two-dimensional (2D) hydrogen–bonded organic frameworks (HOFs), HOF-10x (x=0,1,2), self-assembled from pyrene-based tectons with systematic elongation of π-conjugated molecular arms. This strategy successfully avoids interpene-tration or staggered stacking and expands the pore size of HOF materials to access mesoporous HOF-102, which features a surface area of ~ 2,500 m2/g and the largest pore volume (1.3 cm3/g) to date among all reported HOFs. More importantly, HOF-102 shows significantly enhanced thermal and chemical stability as evidenced by powder x-ray diffraction and N2 isotherms after treatments in chal-lenging conditions. Such stability enables the adsorption of dyes and cytochrome c from aqueous media by HOF-102 and affords a processible HOF-102/fiber composite for the efficient photochemical detox-ification of a mustard gas simulant.

Examination of Aggregation Induced Enhanced Emission in a Propeller Shaped Chiral- Nonconjugated Blue Emitter from Restricted Intramolecular Rotation and J Type π⋯π Stacking Interactions

2021 ◽  
Author(s):  
Gul Yakali
Keyword(s):  
Thin Film ◽  
Small Molecules ◽  
Solid Phase ◽  
Stacking Interactions ◽  
Optoelectronic Materials ◽  
Π Stacking ◽  
Intramolecular Rotation

Fluorescent organic small molecules with the property of aggregation induced enhanced emission in the solid phase (crystall or thin film) have great attention for the design of optoelectronic materials. Generally,...

X-ray Crystal Structure of Gallium Tris- (8-hydroxyquinoline):  Intermolecular π−π Stacking Interactions in the Solid State

1999 ◽  
Vol 11 (3) ◽  
pp. 530-532 ◽  
Author(s):  
Yue Wang ◽  
Weixing Zhang ◽  
Yanqin Li ◽  
Ling Ye ◽  
Guangdi Yang
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Stacking Interactions ◽  
X Ray ◽  
Π Stacking

A macrocyclic [60]fullerene–porphyrin dyad involving π–π stacking interactions

1998 ◽  
pp. 1981-1982 ◽  
Author(s):  
Elke Dietel ◽  
Andreas Hirsch ◽  
Emerich Eichhorn ◽  
Anton Rieker ◽  
Steffen Hackbarth ◽  
...  
Keyword(s):  
Stacking Interactions ◽  
Π Stacking

scholarly journals Isomeric 4,2′:6′,4″- and 3,2′:6′,3″-Terpyridines with Isomeric 4′-Trifluoromethylphenyl Substituents: Effects on the Assembly of Coordination Polymers with [Cu(hfacac)2] (Hhfacac = Hexafluoropentane-2,4-dione)

Inorganics ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 54
Author(s):  
Giacomo Manfroni ◽  
Simona S. Capomolla ◽  
Alessandro Prescimone ◽  
Edwin C. Constable ◽  
Catherine E. Housecroft
Keyword(s):  
Coordination Polymers ◽  
Metal Binding ◽  
Polymer Chains ◽  
Stacking Interactions ◽  
X Ray Diffraction ◽  
Preparative Scale ◽  
X Ray ◽  
Single Crystal Structures ◽  
Π Stacking ◽  
Packing Interactions

The isomers 4′-(4-(trifluoromethyl)phenyl)-4,2′:6′,4″-terpyridine (1), 4′-(3-(trifluoromethyl)phenyl)-4,2′:6′,4″-terpyridine (2), 4′-(4-(trifluoromethyl)phenyl)-3,2′:6′,3″-terpyridine (3), and 4′-(3-(trifluoromethyl)phenyl)-3,2′:6′,3″-terpyridine (4) have been prepared and characterized. The single crystal structures of 1 and 2 were determined. The 1D-polymers [Cu2(hfacac)4(1)2]n.2nC6H4Cl2 (Hhfacac = 1,1,1,5,5,5-hexafluoropentane-2,4-dione), [Cu(hfacac)2(2)]n.2nC6H5Me, [Cu2(hfacac)4(3)2]n.nC6H4Cl2, [Cu2(hfacac)4(3)2]n.nC6H5Cl, and [Cu(hfacac)2(4)]n.nC6H5Cl have been formed by reactions of 1, 2, 3 and 4 with [Cu(hfacac)2].H2O under conditions of crystal growth by layering and four of these coordination polymers have been formed on a preparative scale. [Cu2(hfacac)4(1)2]n.2nC6H4Cl2 and [Cu(hfacac)2(2)]n.2nC6H5Me are zig-zag chains and the different substitution position of the CF3 group in 1 and 2 does not affect this motif. Packing of the polymer chains is governed mainly by C–F...F–C contacts, and there are no inter-polymer π-stacking interactions. The conformation of the 3,2′:6′,3″-tpy unit in [Cu2(hfacac)4(3)2]n.nC6H4Cl2 and [Cu(hfacac)2(4)]n.nC6H5Cl differs, leading to different structural motifs in the 1D-polymer backbones. In [Cu(hfacac)2(4)]n.nC6H5Cl, the peripheral 3-CF3C6H4 unit is accommodated in a pocket between two {Cu(hfacac)2} units and engages in four C–Hphenyl...F–Chfacac contacts which lock the phenylpyridine unit in a near planar conformation. In [Cu2(hfacac)4(3)2]n.nC6H4Cl2 and [Cu(hfacac)2(4)]n.nC6H5Cl, π-stacking interactions between 4′-trifluoromethylphenyl-3,2′:6′,3″-tpy domains are key packing interactions, and this contrasts with the packing of polymers incorporating 1 and 2. We use powder X-ray diffraction to demonstrate that the assemblies of the coordination polymers are reproducible, and that a switch from a 4,2′:6′,4″- to 3,2′:6′,3″-tpy metal-binding unit is accompanied by a change from dominant C–F...F–C and C–F...H–C contacts to π-stacking of arene domains between ligands 3 or 4.

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