scholarly journals Structured Waters Mediate Small Molecule Binding to G-Quadruplex Nucleic Acids

2021 ◽  
Vol 15 (1) ◽  
pp. 7
Author(s):  
Stephen Neidle
Keyword(s):  
Crystal Structures ◽  
Small Molecule ◽  
Drug Targets ◽  
Bound Water ◽  
Water Molecules ◽  
Telomeric Dna ◽  
Naphthalene Diimide ◽  
In Silico Studies ◽  
G Quadruplex

The role of G-quadruplexes in human cancers is increasingly well-defined. Accordingly, G-quadruplexes can be suitable drug targets and many small molecules have been identified to date as G-quadruplex binders, some using computer-based design methods and co-crystal structures. The role of bound water molecules in the crystal structures of G-quadruplex-small molecule complexes has been analyzed in this study, focusing on the water arrangements in several G-quadruplex ligand complexes. One is the complex between the tetrasubstituted naphthalene diimide compound MM41 and a human intramolecular telomeric DNA G-quadruplex, and the others are in substituted acridine bimolecular G-quadruplex complexes. Bridging water molecules form most of the hydrogen-bond contacts between ligands and DNA in the parallel G-quadruplex structures examined here. Clusters of structured water molecules play essential roles in mediating between ligand side chain groups/chromophore core and G-quadruplex. These clusters tend to be conserved between complex and native G-quadruplex structures, suggesting that they more generally serve as platforms for ligand binding, and should be taken into account in docking and in silico studies.

Extrem asymmetrisch gebundene Wassermoleküle-Kristallstrukturen von Sr(OH)Cl · 4 H2O, Sr(OH)Br · 4 H2O und Ba(OH)I·4 H2O / Extremely Asymmetrically Bound Water Molecules-Crystal Structures of Sr(OH)Cl · 4 H2O, Sr(OH)Br · 4 H2O, and Ba(OH)I·4 H2O

1991 ◽  
Vol 46 (10) ◽  
pp. 1279-1286 ◽  
Author(s):  
Thomas Kellersohn ◽  
Konrad Beckenkamp ◽  
Heinz Dieter Lutz
Keyword(s):  
Crystal Structures ◽  
Bound Water ◽  
Structure Type ◽  
Water Molecules ◽  
Halide Ions ◽  
Weak Hydrogen Bond ◽  
Scanning Calorimetry ◽  
Unknown Structure ◽  
Stretching Vibrations ◽  
Strong Distortion

The crystal structures of isotypic Sr(OH)Cl ·4 H2O, Sr(OH)Br·4 H2O, and Ba(OH)I·4 H2O are reported. The title compounds crystallize in a hitherto unknown structure type, space group PĪ, Z = 2. The final R values obtained are 0.0261, 0.069, and 0.062, respectively. The coordination of the metal ions is monocapped square antiprismatic with 7 H2O, 1 OH- and 1 halide ion. The halide ions separate metal/water/hydroxide layers. Each of the four crystallographically different water molecules serves as donor for one very strong and one very weak hydrogen bond and, hence, is extremely asymmetrically bound. Owing to this strong distortion, the largest one known so far, the OH stretching vibrations of the H2O molecules are intramolecularly decoupled as shown from vibrational spectra. The enthalpies of dehydration obtained from differential scanning calorimetry are reported.

scholarly journals Forever Young: Structural Stability of Telomeric Guanine-Quadruplexes in Presence of Oxidative DNA Lesions

2020 ◽  
Author(s):  
Tom Miclot ◽  
Camille Corbier ◽  
Alessio Terenzi ◽  
Cécilia Hognon ◽  
Stéphanie Grandemange ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Molecular Dynamics ◽  
Structural Stability ◽  
Md Simulations ◽  
Dna Lesions ◽  
Computational Investigation ◽  
Telomeric Dna ◽  
G Quadruplex ◽  
The Stability

AbstractHuman telomeric DNA (h-Telo), in G-quadruplex (G4) conformation, is characterized by a remarkable structural stability that confers it the capacity to resist to oxidative stress producing one or even clustered 8-oxoguanine lesions. We present a combined experimental/computational investigation, by using circular dichroism in aqueous solutions, cellular immunofluorescence assays and molecular dynamics (MD) simulations, that identifies the crucial role of the stability of G4s to oxidative lesions, related also to their biological role as inhibitors of telomerase, an enzyme overexpressed in most cancers associated to oxidative stress.

scholarly journals The role of protein-bound water molecules in microbial rhodopsins

2014 ◽  
Vol 1837 (5) ◽  
pp. 606-613 ◽  
Author(s):  
Klaus Gerwert ◽  
Erik Freier ◽  
Steffen Wolf
Keyword(s):  
Bound Water ◽  
Water Molecules

scholarly journals Rational Design and Synthesis of Naphthalene Diimide Linked Bis-Naphthalimides as DNA Interactive Agents

2021 ◽  
Vol 9 ◽  
Author(s):  
M. Shaheer Malik ◽  
Syed Farooq Adil ◽  
Ziad Moussa ◽  
Hatem M. Altass ◽  
Ismail I. Althagafi ◽  
...  
Keyword(s):  
Rational Design ◽  
Thermal Denaturation ◽  
Telomeric Dna ◽  
Docking Analysis ◽  
Design And Synthesis ◽  
Naphthalene Diimide ◽  
G Quadruplex ◽  
Further Development ◽  
Molecular Docking Analysis ◽  
Better Than

A molecular modeling assisted rational design and synthesis of naphthalene diimide linked bis-naphthalimides as potential DNA interactive agents is described. Chemical templates incorporating naphthalene diimide as a linker in bis-naphthalimide motif were subjected to molecular docking analysis at specific intercalation and telomeric DNA G-quadruplex sites. Excellent results were obtained, which were better than the standards. A short and convenient synthetic route was employed to access these hybrids experimentally, followed by evaluation of their ability to cause thermal denaturation of DNA and cytotoxic properties along with ADME predictions. The obtained results provided useful insights and two potential molecules were identified for further development.

scholarly journals Detection of genomic G-quadruplexes in living cells using a small artificial protein

2020 ◽  
Vol 48 (20) ◽  
pp. 11706-11720
Author(s):  
Ke-wei Zheng ◽  
Jia-yu Zhang ◽  
Yi-de He ◽  
Jia-yuan Gong ◽  
Cui-jiao Wen ◽  
...  
Keyword(s):  
Drug Targets ◽  
Fold Increase ◽  
Living Cells ◽  
Molecular Devices ◽  
Genome Wide ◽  
G Quadruplex ◽  
Artificial Protein ◽  
Important Drug ◽  
Sequence Identities

Abstract G-quadruplex (G4) structures formed by guanine-rich nucleic acids are implicated in essential physiological and pathological processes and serve as important drug targets. The genome-wide detection of G4s in living cells is important for exploring the functional role of G4s but has not yet been achieved due to the lack of a suitable G4 probe. Here we report an artificial 6.7 kDa G4 probe (G4P) protein that binds G4s with high affinity and specificity. We used it to capture G4s in living human, mouse, and chicken cells with the ChIP-Seq technique, yielding genome-wide landscape as well as details on the positions, frequencies, and sequence identities of G4 formation in these cells. Our results indicate that transcription is accompanied by a robust formation of G4s in genes. In human cells, we detected up to >123 000 G4P peaks, of which >1/3 had a fold increase of ≥5 and were present in >60% promoters and ∼70% genes. Being much smaller than a scFv antibody (27 kDa) or even a nanobody (12–15 kDa), we expect that the G4P may find diverse applications in biology, medicine, and molecular devices as a G4 affinity agent.

scholarly journals Water spines and networks in G-quadruplex structures

2020 ◽  
Author(s):  
Kevin Li ◽  
Liliya Yatsunyk ◽  
Stephen Neidle
Keyword(s):  
Hydrogen Bond ◽  
High Resolution ◽  
Water Molecule ◽  
Crystal Structures ◽  
Water Molecules ◽  
Nmr Structures ◽  
Loop Conformations ◽  
G Quadruplex ◽  
Guanine Base ◽  
Loop Regions

Abstract Quadruplex DNAs can fold into a variety of distinct topologies, depending in part on loop types and orientations of individual strands, as shown by high-resolution crystal and NMR structures. Crystal structures also show associated water molecules. We report here on an analysis of the hydration arrangements around selected folded quadruplex DNAs, which has revealed several prominent features that re-occur in related structures. Many of the primary-sphere water molecules are found in the grooves and loop regions of these structures. At least one groove in anti-parallel and hybrid quadruplex structures is long and narrow and contains an extensive spine of linked primary-sphere water molecules. This spine is analogous to but fundamentally distinct from the well-characterized spine observed in the minor groove of A/T-rich duplex DNA, in that every water molecule in the continuous quadruplex spines makes a direct hydrogen bond contact with groove atoms, principally phosphate oxygen atoms lining groove walls and guanine base nitrogen atoms on the groove floor. By contrast, parallel quadruplexes do not have extended grooves, but primary-sphere water molecules still cluster in them and are especially associated with the loops, helping to stabilize loop conformations.

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