The enolase superfamily: A general strategy for enzyme-catalyzed abstraction of the α-protons of carboxylic acids

Patricia C. Babbitt, Miriam S. Hasson, Joseph E. Wedekind, David R.J. Palmer, William C. Barrett, George H. Reed, Ivan Rayment, Dagmar Ringe, George L. Kenyon, John A. Gerlt

Research output: Contribution to journalArticle

Abstract

We have discovered a superfamily of enzymes related by their ability to catalyze the abstraction of the α-proton of a carboxylic acid to form an enolic intermediate. Although each reaction catalyzed by these enzymes is initiated by this common step, their overall reactions (including racemization, β-elimination of water, β-elimination of ammonia, and cycloisomerization) as well as the stereochemical consequences (syn vs anti) of the β-elimination reactions are diverse. Analysis of sequence and structural similarities among these proteins suggests that all of their chemical reactions are mediated by a common active site architecture modified through evolution to allow the enolic intermediates to partition to different products in their respective active sites via different overall mechanisms. All of these enzymes retain the ability to catalyze the thermodynamically difficult step of proton abstraction. These homologous proteins, designated the 'enolase superfamily', include enolase as well as more metabolically specialized enzymes: mandelate racemase, galactonate dehydratase, glucarate dehydratase, muconate-lactonizing enzymes, N-acylamino acid racemase, β- methylaspartate ammonia-lyase, and o-succinylbenzoate synthase. Comparative analysis of structure-function relationships within the superfamily suggests that carboxyphosphonoenolpyruvate synthase, another member of the superfamily, does not catalyze the reaction proposed in the literature but catalyzes an enolase-like reaction instead. The established and deduced structure-function relationships in the superfamily allow the prediction that other apparent members of the family for which no catalytic functions have yet been assigned will also perform chemistry involving abstraction of the α-protons of carboxylic acids.

Original languageEnglish (US)
Pages (from-to)16489-16501
Number of pages13
JournalBiochemistry
Volume35
Issue number51
DOIs
StatePublished - Dec 24 1996
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry

Fingerprint Dive into the research topics of 'The enolase superfamily: A general strategy for enzyme-catalyzed abstraction of the α-protons of carboxylic acids'. Together they form a unique fingerprint.

  • Cite this

    Babbitt, P. C., Hasson, M. S., Wedekind, J. E., Palmer, D. R. J., Barrett, W. C., Reed, G. H., Rayment, I., Ringe, D., Kenyon, G. L., & Gerlt, J. A. (1996). The enolase superfamily: A general strategy for enzyme-catalyzed abstraction of the α-protons of carboxylic acids. Biochemistry, 35(51), 16489-16501. https://doi.org/10.1021/bi9616413