scholarly journals X-ray Structure and Ligand Binding Study of a Moth Chemosensory Protein

2002 ◽  
Vol 277 (35) ◽  
pp. 32094-32098 ◽  
Author(s):  
Audrey Lartigue ◽  
Valérie Campanacci ◽  
Alain Roussel ◽  
Anna M. Larsson ◽  
T. Alwyn Jones ◽  
...  
Keyword(s):  
Ligand Binding ◽  
Binding Study ◽  
X Ray ◽  
Chemosensory Protein

scholarly journals A drug discovery-oriented non-invasive protocol for protein crystal cryoprotection by dehydration, with application for crystallization screening.

2021 ◽  
Author(s):  
Dom Bellini
Keyword(s):  
Drug Discovery ◽  
Ligand Binding ◽  
Protein Crystal ◽  
Macromolecular Crystallography ◽  
X Ray ◽  
Water Fraction ◽  
Non Invasive ◽  
Vapour Diffusion ◽  
Large Compound ◽  
Fragment Libraries

In X-ray macromolecular crystallography, cryoprotection of crystals mounted on harvesting loops is achieved when the water in the sample solvent transitions to vitreous ice before crystalline ice forms. This is achieved by rapid cooling in liquid nitrogen or propane. Protocols for protein crystal cryoprotection are based on either increasing environmental pressure or reducing the water fraction in the solvent. This study presents a new protocol for cryoprotecting crystals. It is based on vapour diffusion dehydration of the crystal drop to reduce the water fraction in the solvent by adding a highly concentrated salt solution, 13 M potassium formate (KF13), directly to the reservoir. Cryoprotection by the KF13 protocol is non-invasive to the crystal, high throughput, not labour intensive, can benefit diffraction resolution and ligand binding, and is very useful in cases with high redundancy such as drug discovery projects which utilize very large compound or fragment libraries. Moreover, an application of KF13 to discover new crystal hits from clear drops of equilibrated crystallization screening plates is also shown.

scholarly journals Probing G-quadruplex topologies and recognition concurrently in real time and 3D using a dual-app nucleoside probe

2019 ◽  
Vol 47 (12) ◽  
pp. 6059-6072 ◽  
Author(s):  
Ashok Nuthanakanti ◽  
Ishtiyaq Ahmed ◽  
Saddam Y Khatik ◽  
Kayarat Saikrishnan ◽  
Seergazhi G Srivatsan
Keyword(s):  
Nucleic Acid ◽  
Ligand Binding ◽  
Real Time ◽  
Telomeric Dna ◽  
X Ray ◽  
X Ray Crystallography ◽  
New Class ◽  
Loop Region ◽  
Dna Repeat ◽  
G Quadruplex

Abstract Comprehensive understanding of structure and recognition properties of regulatory nucleic acid elements in real time and atomic level is highly important to devise efficient therapeutic strategies. Here, we report the establishment of an innovative biophysical platform using a dual-app nucleoside analog, which serves as a common probe to detect and correlate different GQ structures and ligand binding under equilibrium conditions and in 3D by fluorescence and X-ray crystallography techniques. The probe (SedU) is composed of a microenvironment-sensitive fluorophore and an excellent anomalous X-ray scatterer (Se), which is assembled by attaching a selenophene ring at 5-position of 2′-deoxyuridine. SedU incorporated into the loop region of human telomeric DNA repeat fluorescently distinguished subtle differences in GQ topologies and enabled quantify ligand binding to different topologies. Importantly, anomalous X-ray dispersion signal from Se could be used to determine the structure of GQs. As the probe is minimally perturbing, a direct comparison of fluorescence data and crystal structures provided structural insights on how the probe senses different GQ conformations without affecting the native fold. Taken together, our dual-app probe represents a new class of tool that opens up new experimental strategies to concurrently investigate nucleic acid structure and recognition in real time and 3D.

scholarly journals X-ray Structures of Progesterone Receptor Ligand Binding Domain in Its Agonist State Reveal Differing Mechanisms for Mixed Profiles of 11β-Substituted Steroids

2012 ◽  
Vol 287 (24) ◽  
pp. 20333-20343 ◽  
Author(s):  
Scott J. Lusher ◽  
Hans C. A. Raaijmakers ◽  
Diep Vu-Pham ◽  
Bert Kazemier ◽  
Rolien Bosch ◽  
...  
Keyword(s):  
Progesterone Receptor ◽  
Ligand Binding ◽  
Binding Domain ◽  
Ligand Binding Domain ◽  
Receptor Ligand ◽  
X Ray

scholarly journals NovelFeIIandCoIIComplexes of Natural Product Tryptanthrin: Synthesis and Binding with G-Quadruplex DNA

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Yi-ning Zhong ◽  
Yan Zhang ◽  
Yun-qiong Gu ◽  
Shi-yun Wu ◽  
Wen-ying Shen ◽  
...  
Keyword(s):  
Natural Products ◽  
Ligand Binding ◽  
Single Crystal ◽  
Natural Product ◽  
Significant Interaction ◽  
Rational Design ◽  
X Ray Diffraction ◽  
Quadruplex Dna ◽  
X Ray ◽  
G Quadruplex

Tryptanthrin is one of the most important members of indoloquinoline alkaloids. We obtained this alkaloid fromIsatis. Two novelFeIIandCoIIcomplexes of tryptanthrin were first synthesized. Single-crystal X-ray diffraction analyses show that these complexes display distorted four-coordinated tetrahedron geometry via two heterocyclic nitrogen and oxygen atoms from tryptanthrin ligand. Binding with G-quadruplex DNA properties revealed that both complexes were found to exhibit significant interaction with G-quadruplex DNA. This study may potentially serve as the basis of future rational design of metal-based drugs from natural products that target the G-quadruplex DNA.

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