Major enhancement of the affinity of an enzyme for a transition-state analog by a single hydroxyl group

Science ◽  
1989 ◽  
Vol 243 (4898) ◽  
pp. 1591-1593 ◽  
Author(s):  
W. Kati ◽  
R Wolfenden
Keyword(s):  
Transition State ◽  
Hydroxyl Group ◽  
Transition State Analog

scholarly journals Structural Insights into Inhibition of the Acinetobacter-Derived Cephalosporinase ADC-7 by Ceftazidime and Its Boronic Acid Transition State Analog

2020 ◽  
Vol 64 (12) ◽  
Author(s):  
Brandy N. Curtis ◽  
Kali A. Smolen ◽  
Sara J. Barlow ◽  
Emilia Caselli ◽  
Fabio Prati ◽  
...  
Keyword(s):  
Transition State ◽  
Boronic Acid ◽  
Carbonyl Oxygen ◽  
Hydroxyl Group ◽  
Side Chain ◽  
Enzyme Complex ◽  
Content Type ◽  
Transition State Analog ◽  
Hydrolysis Of ◽  
Structural Insights

ABSTRACT Extended-spectrum class C β-lactamases have evolved to rapidly inactivate expanded-spectrum cephalosporins, a class of antibiotics designed to be resistant to hydrolysis by β-lactamase enzymes. To better understand the mechanism by which Acinetobacter-derived cephalosporinase-7 (ADC-7), a chromosomal AmpC enzyme, hydrolyzes these molecules, we determined the X-ray crystal structure of ADC-7 in an acyl-enzyme complex with the cephalosporin ceftazidime (2.40 Å) as well as in complex with a boronic acid transition state analog inhibitor that contains the R1 side chain of ceftazidime (1.67 Å). In the acyl-enzyme complex, the carbonyl oxygen is situated in the oxyanion hole where it makes key stabilizing interactions with the main chain nitrogens of Ser64 and Ser315. The boronic acid O1 hydroxyl group is similarly positioned in this area. Conserved residues Gln120 and Asn152 form hydrogen bonds with the amide group of the R1 side chain in both complexes. These complexes represent two steps in the hydrolysis of expanded-spectrum cephalosporins by ADC-7 and offer insight into the inhibition of ADC-7 by ceftazidime through displacement of the deacylating water molecule as well as blocking its trajectory to the acyl carbonyl carbon. In addition, the transition state analog inhibitor, LP06, was shown to bind with high affinity to ADC-7 (Ki, 50 nM) and was able to restore ceftazidime susceptibility, offering the potential for optimization efforts of this type of inhibitor.

Renin inhibitors. Synthesis of transition-state analog inhibitors containing phosphorus acid derivatives at the scissile bond

1989 ◽  
Vol 32 (7) ◽  
pp. 1652-1661 ◽  
Author(s):  
Mark C. Allen ◽  
Walter Fuhrer ◽  
Brian Tuck ◽  
Roy Wade ◽  
Jeanette M. Wood
Keyword(s):  
Transition State ◽  
Phosphorus Acid ◽  
Transition State Analog ◽  
Renin Inhibitors ◽  
Scissile Bond

scholarly journals A crystallographic study of the Toho-1 β-lactamase acylation mechanism

2014 ◽  
Vol 70 (a1) ◽  
pp. C1207-C1207
Author(s):  
Leighton Coates
Keyword(s):  
Hydrogen Bonding ◽  
Transition State ◽  
Active Site ◽  
Catalytic Mechanism ◽  
Substrate Binding ◽  
Ligand Complex ◽  
Transition State Analog ◽  
Hydrogen Bonding Interactions ◽  
Active Site Region ◽  
Neutron Crystallography

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].

Phosphonamidates as transition-state analog inhibitors of thermolysin

Biochemistry ◽  
1983 ◽  
Vol 22 (20) ◽  
pp. 4618-4624 ◽  
Author(s):  
Paul A. Bartlett ◽  
Charles K. Marlowe
Keyword(s):  
Transition State ◽  
Transition State Analog
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