scholarly journals Extreme Catalytic Power of Ketosteroid Isomerase Related to the Reversal of Proton Dislocations in Hydrogen-Bond Network

2020 ◽  
Vol 124 (18) ◽  
pp. 3661-3666 ◽  
Author(s):  
Paweł Kędzierski ◽  
Maria Zaczkowska ◽  
W. Andrzej Sokalski
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bond Network ◽  
Ketosteroid Isomerase ◽  
Bond Network ◽  
Catalytic Power

scholarly journals Structural double-mutant cycle analysis of a hydrogen bond network in ketosteroid isomerase from Pseudomonas putida biotype B

2004 ◽  
Vol 382 (3) ◽  
pp. 967-973 ◽  
Author(s):  
Do Soo JANG ◽  
Hyung Jin CHA ◽  
Sun-Shin CHA ◽  
Bee Hak HONG ◽  
Nam-Chul HA ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Pseudomonas Putida ◽  
Double Mutant ◽  
Isomerization Reaction ◽  
Hydrogen Bond Network ◽  
Coupling Energy ◽  
Ketosteroid Isomerase ◽  
Bond Network ◽  
Double Mutant Cycle

KSI (ketosteroid isomerase) catalyses an allylic isomerization reaction at a diffusion-controlled rate. A hydrogen bond network, Asp99···Water504···Tyr14···Tyr55···Tyr30, connects two critical catalytic residues, Tyr14 and Asp99, with Tyr30, Tyr55 and a water molecule in the highly apolar active site of the Pseudomonas putida KSI. In order to characterize the interactions among these amino acids in the hydrogen bond network of KSI, double-mutant cycle analysis was performed, and the crystal structure of each mutant protein within the cycle was determined respectively to interpret the coupling energy. The ΔΔGo values of Y14F/D99L (Tyr14→Phe/Asp99→Leu) KSI, 25.5 kJ/mol for catalysis and 28.9 kJ/mol for stability, were smaller than the sums (i.e. 29.7 kJ/mol for catalysis and 34.3 kJ/mol for stability) for single mutant KSIs respectively, indicating that the effect of the Y14F/D99L mutation was partially additive for both catalysis and stability. The partially additive effect of the Y14F/D99L mutation suggests that Tyr14 and Asp99 should interact positively for the stabilization of the transition state during the catalysis. The crystal structure of Y14F/D99L KSI indicated that the Y14F/D99L mutation increased the hydrophobic interaction while disrupting the hydrogen bond network. The ΔΔGo values of both Y30F/D99L and Y55F/D99L KSIs for the catalysis and stability were larger than the sum of single mutants, suggesting that either Tyr30 and Asp99 or Tyr55 and Asp99 should interact negatively for the catalysis and stability. These synergistic effects of both Y30F/D99L and Y55F/D99L mutations resulted from the disruption of the hydrogen bond network. The synergistic effect of the Y55F/D99L mutation was larger than that of the Y30F/D99L mutation, since the former mutation impaired the proper positioning of a critical catalytic residue, Tyr14, involved in the catalysis of KSI. The present study can provide insight into interpreting the coupling energy measured by double-mutant cycle analysis based on the crystal structures of the wild-type and mutant proteins.

Halides of Macrocyclic Silver(II) Complexes: Crystal Structures with Hydrogen Bond Network and Reaction Kinetics of the Decomposition

2021 ◽  
pp. 120431
Author(s):  
Akinori Honda ◽  
Shunta Kakihara ◽  
Shuhei Ichimura ◽  
Kazuaki Tomono ◽  
Mina Matsushita ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Reaction Kinetics ◽  
Crystal Structures ◽  
Hydrogen Bond Network ◽  
Bond Network ◽  
Kinetics Of

scholarly journals Hydrogen‐Bond Network Determines the Early Photoisomerization of Cph1 and AnPixJ Phytochromes

2021 ◽  
Author(s):  
Xiang-Yang Liu ◽  
Teng-Shuo Zhang ◽  
Qiu Fang ◽  
Wei-Hai Fang ◽  
Leticia González ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bond Network ◽  
Bond Network

Supramolecular assembling using synthons with NH—CO(S)—CS—NH and NH—CO—CO—NH functionalities: crystal structures of (S,S)-N,N′-monothiooxalyldileucine methyl ester and its dithio analogue

2004 ◽  
Vol 60 (1) ◽  
pp. 90-96 ◽  
Author(s):  
Biserka Kojić-Prodić ◽  
Berislav Perić ◽  
Zoran Štefanić ◽  
Anton Meden ◽  
Janja Makarević ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Methyl Ester ◽  
Crystal Structures ◽  
Hydrogen Bond Network ◽  
Asymmetric Unit ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
Bond Network ◽  
Bonding Systems

To compare the structural properties of oxalamide and thiooxalamide groups in the formation of hydrogen bonds suitable for supramolecular assemblies a series of retropeptides was studied. Some of them, having oxalamide bridges, are gelators of organic solvents and water. However, retropeptides with oxygen replaced by the sp 2 sulfur have not exhibited such properties. The crystal structures of the two title compounds are homostructural, i.e. they have similar packing arrangements. The monothio compound crystallizes in the orthorhombic space group P212121 with two molecules in the asymmetric unit arranged in a hydrogen-bond network with an approximate 41 axis along the crystallographic b axis. However, the dithio and dioxo analogues crystallize in the tetragonal space group P41 with similar packing patterns and hydrogen-bonding systems arranged in agreement with a crystallographic 41 axis. Thus, these two analogues are isostructural having closely related hydrogen-bonding patterns in spite of the different size and polarity of oxygen and sulfur which serve as the proton acceptors.

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