A Catalytic Diad Involved in Substrate-Assisted Catalysis:  NMR Study of Hydrogen Bonding and Dynamics at the Active Site of Phosphatidylinositol-Specific Phospholipase C†

Biochemistry ◽  
2001 ◽  
Vol 40 (32) ◽  
pp. 9743-9750 ◽  
Author(s):  
Margret Ryan ◽  
Tun Liu ◽  
Frederick W. Dahlquist ◽  
O. Hayes Griffith

2000 ◽  
Vol 275 (2) ◽  
pp. 742-751 ◽  
Author(s):  
Bao D. Nguyen ◽  
Zhicheng Xia ◽  
Francesca Cutruzzolá ◽  
Carlo Travaglini Allocatelli ◽  
Maurizio Brunori ◽  
...  


1998 ◽  
Vol 7 ◽  
pp. 1426-1428 ◽  
Author(s):  
T. Aizawa ◽  
O. Sato ◽  
Y. Ikushima ◽  
K. Hatakeda ◽  
N. Saito


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Dariusz Czernecki ◽  
Pierre Legrand ◽  
Mustafa Tekpinar ◽  
Sandrine Rosario ◽  
Pierre-Alexandre Kaminski ◽  
...  

AbstractBacteriophages have long been known to use modified bases in their DNA to prevent cleavage by the host’s restriction endonucleases. Among them, cyanophage S-2L is unique because its genome has all its adenines (A) systematically replaced by 2-aminoadenines (Z). Here, we identify a member of the PrimPol family as the sole possible polymerase of S-2L and we find it can incorporate both A and Z in front of a T. Its crystal structure at 1.5 Å resolution confirms that there is no structural element in the active site that could lead to the rejection of A in front of T. To resolve this contradiction, we show that a nearby gene is a triphosphohydolase specific of dATP (DatZ), that leaves intact all other dNTPs, including dZTP. This explains the absence of A in S-2L genome. Crystal structures of DatZ with various ligands, including one at sub-angstrom resolution, allow to describe its mechanism as a typical two-metal-ion mechanism and to set the stage for its engineering.



2017 ◽  
Vol 15 (36) ◽  
pp. 7572-7579 ◽  
Author(s):  
Antonio J. Mota ◽  
Jürgen Neuhold ◽  
Martina Drescher ◽  
Sébastien Lemouzy ◽  
Leticia González ◽  
...  

Experimental and computational evidence for unusual intramolecular hydrogen-bonding interactions is presented and discussed.



2019 ◽  
Author(s):  
Jifu Duan ◽  
Stefan Mebs ◽  
Moritz Senger ◽  
Konstantin Laun ◽  
Florian Wittkamp ◽  
...  

The H2 conversion and CO inhibition reactivity of nine [FeFe]-hydrogenase constructs with semi-artificial cofactors was studied by in situ and time-resolved infrared spectroscopy, X-ray crystallography, and theoretical methods. Impaired hydrogen turnover and proton transfer as well as characteristic CO inhibition/ reactivation kinetics are assigned to varying degrees of hydrogen-bonding interactions at the active site. We show that the probability to adopt catalytic intermediates is modulated by intramolecular and protein-cofactor interactions that govern structural dynamics at the active site of [FeFe]-hydrogenases.<br>



2014 ◽  
Vol 70 (a1) ◽  
pp. C1207-C1207
Author(s):  
Leighton Coates

β-lactam antibiotics have been used effectively over several decades against many types of highly virulent bacteria. The predominant cause of resistance to these antibiotics in Gram-negative bacterial pathogens is the production of serine β-lactamase enzymes. A key aspect of the class A serine β-lactamase mechanism that remains unresolved and controversial is the identity of the residue acting as the catalytic base during the acylation reaction. Multiple mechanisms have been proposed for the formation of the acyl-enzyme intermediate that are predicated on understanding the protonation states and hydrogen-bonding interactions among the important residues involved in substrate binding and catalysis of these enzymes. For resolving a controversy of this nature surrounding the catalytic mechanism, neutron crystallography is a powerful complement to X-ray crystallography that can explicitly determine the location of deuterium atoms in proteins, thereby directly revealing the hydrogen-bonding interactions of important amino acid residues. Neutron crystallography was used to unambiguously reveal the ground-state active site protonation states and the resulting hydrogen-bonding network in two ligand-free Toho-1 β-lactamase mutants which provided remarkably clear pictures of the active site region prior to substrate binding and subsequent acylation [1,2] and an acylation transition-state analog, benzothiophene-2-boronic acid (BZB), which was also isotopically enriched with 11B. The neutron structure revealed the locations of all deuterium atoms in the active site region and clearly indicated that Glu166 is protonated in the BZB transition-state analog complex. As a result, the complete hydrogen-bonding pathway throughout the active site region could then deduced for this protein-ligand complex that mimics the acylation tetrahedral intermediate [3].



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