scholarly journals Testing Geometrical Discrimination within an Enzyme Active Site: Constrained Hydrogen Bonding in the Ketosteroid Isomerase Oxyanion Hole

2008 ◽  
Vol 130 (41) ◽  
pp. 13696-13708 ◽  
Author(s):  
Paul A. Sigala ◽  
Daniel A. Kraut ◽  
Jose M. M. Caaveiro ◽  
Brandon Pybus ◽  
Eliza A. Ruben ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Active Site ◽  
Ketosteroid Isomerase ◽  
Oxyanion Hole ◽  
Enzyme Active Site

scholarly journals Proton Affinity of the Oxyanion Hole in the Active Site of Ketosteroid Isomerase

Biochemistry ◽  
2010 ◽  
Vol 49 (12) ◽  
pp. 2725-2731 ◽  
Author(s):  
William Childs ◽  
Steven G. Boxer
Keyword(s):  
Proton Affinity ◽  
Active Site ◽  
Ketosteroid Isomerase ◽  
Oxyanion Hole

Hydrogen Bonding at the Active Site of Δ5-3-Ketosteroid Isomerase†

Biochemistry ◽  
1997 ◽  
Vol 36 (48) ◽  
pp. 14616-14626 ◽  
Author(s):  
Qinjian Zhao ◽  
Chitrananda Abeygunawardana ◽  
Apostolos G. Gittis ◽  
Albert S. Mildvan
Keyword(s):  
Hydrogen Bonding ◽  
Active Site ◽  
Ketosteroid Isomerase

scholarly journals Testing Electrostatic Complementarity in Enzyme Catalysis: Hydrogen Bonding in the Ketosteroid Isomerase Oxyanion Hole

PLoS Biology ◽  
2006 ◽  
Vol 4 (4) ◽  
pp. e99 ◽  
Author(s):  
Daniel A Kraut ◽  
Paul A Sigala ◽  
Brandon Pybus ◽  
Corey W Liu ◽  
Dagmar Ringe ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Enzyme Catalysis ◽  
Ketosteroid Isomerase ◽  
Oxyanion Hole

scholarly journals Hydrogen Bonding in the Active Site of Ketosteroid Isomerase: Electronic Inductive Effects and Hydrogen Bond Coupling

Biochemistry ◽  
2010 ◽  
Vol 49 (48) ◽  
pp. 10339-10348 ◽  
Author(s):  
Philip Hanoian ◽  
Paul A. Sigala ◽  
Daniel Herschlag ◽  
Sharon Hammes-Schiffer
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Active Site ◽  
Ketosteroid Isomerase ◽  
Inductive Effects

scholarly journals Dissecting the paradoxical effects of hydrogen bond mutations in the ketosteroid isomerase oxyanion hole

2010 ◽  
Vol 107 (5) ◽  
pp. 1960-1965 ◽  
Author(s):  
Daniel A. Kraut ◽  
Paul A. Sigala ◽  
Timothy D. Fenn ◽  
Daniel Herschlag
Keyword(s):  
Hydrogen Bond ◽  
Active Site ◽  
Site Directed Mutagenesis ◽  
Ketosteroid Isomerase ◽  
X Ray ◽  
Enzyme Active Site ◽  
Hydrogen Bonding Interactions ◽  
Rate Effects ◽  
Paradoxical Effects ◽  
Moderate Rate

The catalytic importance of enzyme active-site interactions is frequently assessed by mutating specific residues and measuring the resulting rate reductions. This approach has been used in bacterial ketosteroid isomerase to probe the energetic importance of active-site hydrogen bonds donated to the dienolate reaction intermediate. The conservative Tyr16Phe mutation impairs catalysis by 105-fold, far larger than the effects of hydrogen bond mutations in other enzymes. However, the less-conservative Tyr16Ser mutation, which also perturbs the Tyr16 hydrogen bond, results in a less-severe 102-fold rate reduction. To understand the paradoxical effects of these mutations and clarify the energetic importance of the Tyr16 hydrogen bond, we have determined the 1.6-Å resolution x-ray structure of the intermediate analogue, equilenin, bound to the Tyr16Ser mutant and measured the rate effects of mutating Tyr16 to Ser, Thr, Ala, and Gly. The nearly identical 200-fold rate reductions of these mutations, together with the 6.4-Å distance observed between the Ser16 hydroxyl and equilenin oxygens in the x-ray structure, strongly suggest that the more moderate rate effect of this mutant is not due to maintenance of a hydrogen bond from Ser at position 16. These results, additional spectroscopic observations, and prior structural studies suggest that the Tyr16Phe mutation results in unfavorable interactions with the dienolate intermediate beyond loss of a hydrogen bond, thereby exaggerating the apparent energetic benefit of the Tyr16 hydrogen bond relative to the solution reaction. These results underscore the complex energetics of hydrogen bonding interactions and site-directed mutagenesis experiments.

scholarly journals A multifunctional surfactant catalyst inspired by hydrolases

2020 ◽  
Vol 6 (14) ◽  
pp. eaaz0404 ◽  
Author(s):  
Mitchell D. Nothling ◽  
Zeyun Xiao ◽  
Nicholas S. Hill ◽  
Mitchell T. Blyth ◽  
Ayana Bhaskaran ◽  
...  
Keyword(s):  
Active Site ◽  
Self Assembly ◽  
Md Simulation ◽  
Hydrolytic Enzymes ◽  
Surfactant Molecule ◽  
Catalytic Triad ◽  
Oxyanion Hole ◽  
Enzyme Active Site ◽  
Close Proximity ◽  
Hydrolysis Of

The remarkable power of enzymes to undertake catalysis frequently stems from their grouping of multiple, complementary chemical units within close proximity around the enzyme active site. Motivated by this, we report here a bioinspired surfactant catalyst that incorporates a variety of chemical functionalities common to hydrolytic enzymes. The textbook hydrolase active site, the catalytic triad, is modeled by positioning the three groups of the triad (-OH, -imidazole, and -CO2H) on a single, trifunctional surfactant molecule. To support this, we recreate the hydrogen bond donating arrangement of the oxyanion hole by imparting surfactant functionality to a guanidinium headgroup. Self-assembly of these amphiphiles in solution drives the collection of functional headgroups into close proximity around a hydrophobic nano-environment, affording hydrolysis of a model ester at rates that challenge α-chymotrypsin. Structural assessment via NMR and XRD, paired with MD simulation and QM calculation, reveals marked similarities of the co-micelle catalyst to native enzymes.

Sign in / Sign up

Export Citation Format

Share Document