scholarly journals Preferred orientation in an angled intercalation site of a chloro-substituted Λ -[Ru(TAP) 2 (dppz)] 2+ complex bound to d(TCGGCGCCGA) 2

Author(s):  
James P. Hall ◽  
Hanna Beer ◽  
Katrin Buchner ◽  
David J. Cardin ◽  
Christine J. Cardin

The crystal structure of the ruthenium DNA ‘light-switch’ complex Λ -[Ru(TAP) 2 (11-Cl-dppz)] 2+ (TAP=tetraazaphenanthrene, dppz=dipyrido[3,2- a ′:2′,3′- c ]phenazine) bound to the oligonucleotide duplex d(TCGGCGCCGA) 2 is reported. The synthesis of the racemic ruthenium complex is described for the first time, and the racemate was used in this study. The crystal structure, at atomic resolution (1.0 Å), shows one ligand as a wedge in the minor groove, resulting in the 51 ° kinking of the double helix, as with the parent Λ -[Ru(TAP) 2 (dppz)] 2+ . Each complex binds to one duplex by intercalation of the dppz ligand and also by semi-intercalation of one of the orthogonal TAP ligands into a second symmetrically equivalent duplex. The 11-chloro substituent binds with the major component (66%) oriented with the 11-chloro substituent on the purine side of the terminal step of the duplex.

Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 298
Author(s):  
Yefen Zhu ◽  
Yanlei Kang ◽  
Ling Zhu ◽  
Kaxi Yu ◽  
Shuai Chen ◽  
...  

Canagliflozin (CG) was a highly effective, selective and reversible inhibitor of sodium-dependent glucose co-transporter 2 developed for the treatment of type 2 diabetes mellitus. The crystal structure of CG monohydrate (CG-H2O) was reported for the first time while CG hemihydrate (CG-Hemi) had been reported in our previous research. Solubility and dissolution rate results showed that the solubility of CG-Hemi was 1.4 times higher than that of CG-H2O in water and hydrochloric acid solution, and the dissolution rates of CG-Hemi were more than 3 folds than CG-H2O in both solutions. Hirshfeld surface analysis showed that CG-H2O had stronger intermolecular forces than CG-Hemi, and water molecules in CG-H2O participated three hydrogen bonds, forming hydrogen bond networks. These crystal structure features might make it more difficult for solvent molecules to dissolve CG-H2O than CG-Hemi. All these analyses might explain why the dissolution performance of CG-Hemi was better than CG-H2O. This work provided an approach to predict the dissolution performance of the drug based on its crystal structure.


RSC Advances ◽  
2016 ◽  
Vol 6 (14) ◽  
pp. 11211-11217 ◽  
Author(s):  
Xue Chen ◽  
Qidi Wang ◽  
Fengzhu Lv ◽  
Paul K. Chu ◽  
Yihe Zhang

RbCaGd(PO4)2:Eu2+ was prepared by the Pechini-type sol–gel method. The crystal structure was determined in the first time. The dipole–dipole interaction plays a major role in the mechanism of concentration quenching of Eu2+ in this phosphor.


1996 ◽  
Vol 35 (10) ◽  
pp. 3050-3052 ◽  
Author(s):  
Bidyut Kumar Santra ◽  
Ganesh A. Thakur ◽  
Prasanta Ghosh ◽  
Amitava Pramanik ◽  
Goutam Kumar Lahiri

Antioxidants ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 946
Author(s):  
Tom E. Forshaw ◽  
Julie A. Reisz ◽  
Kimberly J. Nelson ◽  
Rajesh Gumpena ◽  
J. Reed Lawson ◽  
...  

Human peroxiredoxins (Prx) are a family of antioxidant enzymes involved in a myriad of cellular functions and diseases. During the reaction with peroxides (e.g., H2O2), the typical 2-Cys Prxs change oligomeric structure between higher order (do)decamers and disulfide-linked dimers, with the hyperoxidized inactive state (-SO2H) favoring the multimeric structure of the reduced enzyme. Here, we present a study on the structural requirements for the repair of hyperoxidized 2-Cys Prxs by human sulfiredoxin (Srx) and the relative efficacy of physiological reductants hydrogen sulfide (H2S) and glutathione (GSH) in this reaction. The crystal structure of the toroidal Prx1-Srx complex shows an extended active site interface. The loss of this interface within engineered Prx2 and Prx3 dimers yielded variants more resistant to hyperoxidation and repair by Srx. Finally, we reveal for the first time Prx isoform-dependent use of and potential cooperation between GSH and H2S in supporting Srx activity.


1989 ◽  
Vol 264 (14) ◽  
pp. 7921-7935
Author(s):  
R V Gessner ◽  
C A Frederick ◽  
G J Quigley ◽  
A Rich ◽  
A H J Wang

2018 ◽  
Vol 64 (247) ◽  
pp. 771-780 ◽  
Author(s):  
PAT WONGPAN ◽  
DAVID J. PRIOR ◽  
PATRICIA J. LANGHORNE ◽  
KATHERINE LILLY ◽  
INGA J. SMITH

ABSTRACTWe have mapped the full crystallographic orientation of sea ice using electron backscatter diffraction (EBSD). This is the first time EBSD has been used to study sea ice. Platelet ice is a feature of sea ice near ice shelves. Ice crystals accumulate as an unconsolidated sub-ice platelet layer beneath the columnar ice (CI), where they are subsumed by the advancing sea–ice interface to form incorporated platelet ice (PI). As is well known, in CI the crystal preferred orientation comprises dominantly horizontal c-axes, while PI has c-axes varying between horizontal and vertical. For the first time, this study shows the a-axes of CI and PI are not random. Misorientation analysis has been used to illuminate the possible drivers of these alignments. In CI the misorientation angle distribution from random pairs and neighbour pairs of grains are indistinguishable, indicating the distributions are a consequence of crystal preferred orientation. Geometric selection during growth will develop the a-axis alignment in CI if ice growth in water is fastest parallel to the a-axis, as has previously been hypothesised. In contrast, in PI random-pair and neighbour-pair misorientation distributions are significantly different, suggesting mechanical rotation of crystals at grain boundaries as the most likely explanation.


Sign in / Sign up

Export Citation Format

Share Document