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Structural and mechanistic studies of enolase.
TLDR
expression and characterization of site-specific mutant forms of the yeast enolase have confirmed the roles of amino acid side chains in the catalysis of the first and second steps of the reaction. Expand
Chelation of serine 39 to Mg2+ latches a gate at the active site of enolase: structure of the bis(Mg2+) complex of yeast enolase and the intermediate analog phosphonoacetohydroxamate at 2.1-A
TLDR
The position of the second Mg2+ in the active site provides new insight into the stereochemistry of substrate binding and the structure of a new crystal form of enolase from bakers' yeast is solved to 2.1-A resolution. Expand
Probing nitrogen-sensitive steps in the free-radical-mediated deamination of amino alcohols by ethanolamine ammonia-lyase.
TLDR
Results show that relative heights of kinetic barriers differ among the three substrates such that levels or identities of steady-state intermediates differ, and 15N-sensitive steps are significant contributors to V/K with (S)-2-aminopropanol. Expand
Toward identification of acid/base catalysts in the active site of enolase: comparison of the properties of K345A, E168Q, and E211Q variants.
TLDR
Property of the three mutant proteins in partial reactions were examined to define more clearly the roles of these residues in the catalytic cycle and suggest that Lys 345 functions as the base in the ionization of 2-PGA and that Glu 211 participates in the second step of the reaction. Expand
Functional and structural changes due to a serine to alanine mutation in the active-site flap of enolase.
TLDR
The kinetic results with the S39A variant support the notions that a rate-limiting product release lowers the activity of wild-type enolase with more electrophilic metal ions and that the metal ions are used to acidify the C2-proton of 2-PGA. Expand
Role of metal ions in catalysis by enolase: an ordered kinetic mechanism for a single substrate enzyme.
TLDR
Electron paramagnetic resonance (EPR) data with 17O-labeled forms of phosphoenolpyruvate show that Mn(2+), bound at the lower affinity site, coordinates to one carboxylate oxygen and one phosphate oxygen of the substrate, fully consistent with the crystallographic data. Expand
Structure of the bis divalent cation complex with phosphonoacetohydroxamate at the active site of enolase.
TLDR
Electron paramagnetic resonance (EPR) spectroscopy has been used to map sites of interaction of PhAH with the two divalent cations at the active site of enolase from bakers' yeast to determine the binding of the functional groups on PhAH to Mn2+ at the two metal ion sites. Expand
Reverse protonation is the key to general acid-base catalysis in enolase.
TLDR
The pH dependence of enolase catalysis was studied to understand howEnolase is able to utilize both general acid and general base catalysis in each direction of the reaction at near-neutral pHs and indicates that the dehydration reaction is catalyzed by a small fraction of enzyme that is reverse-protonated, whereas the hydration reaction isalyst by a larger fraction that is typically protonated. Expand
Identification of the substrate radical intermediate derived from ethanolamine during catalysis by ethanolamine ammonia-lyase.
TLDR
The 13C splitting from C1 persists from 10 ms throughout the time course of substrate turnover, and there was no evidence of a detectable amount of a product like radical having unpaired spin on C2, correct an earlier assignment for this radical intermediate. Expand
Role of metal ions in the reaction catalyzed by L-ribulose-5-phosphate 4-epimerase.
TLDR
Data suggest that (1) the substrate coordinates to the enzyme-bound metal ion, (2) His95 and His97 are likely metal ion ligands, and (3) Tyr229 is not a metal ions ligand, but may play another role in catalysis, possibly as an acid-base catalyst. Expand
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