3-Keto-5-aminohexanoate cleavage enzyme: a common fold for an uncommon Claisen-type condensation - Institut Pasteur Access content directly
Journal Articles Journal of Biological Chemistry Year : 2011

3-Keto-5-aminohexanoate cleavage enzyme: a common fold for an uncommon Claisen-type condensation

Marco Bellinzoni
Karine Bastard
Alain Perret
Anne Zaparucha
Nadia Perchat
  • Function : Author
  • PersonId : 920751
Carine Vergne
Raquel C. de Melo-Minardi
  • Function : Author
  • PersonId : 1361926
  • IdRef : 26865896X
François Artiguenave
  • Function : Author
  • PersonId : 908642
Jean Weissenbach
  • Function : Author
  • PersonId : 911249
Marcel Salanoubat

Abstract

The exponential increase in genome sequencing output has led to the accumulation of thousands of predicted genes lacking a proper functional annotation. Among this mass of hypothetical proteins, enzymes catalyzing new reactions or using novel ways to catalyze already known reactions might still wait to be identified. Here, we provide a structural and biochemical characterization of the 3-keto-5-aminohexanoate cleavage enzyme (Kce), an enzymatic activity long known as being involved in the anaerobic fermentation of lysine but whose catalytic mechanism has remained elusive so far. Although the enzyme shows the ubiquitous triose phosphate isomerase (TIM) barrel fold and a Zn(2+) cation reminiscent of metal-dependent class II aldolases, our results based on a combination of x-ray snapshots and molecular modeling point to an unprecedented mechanism that proceeds through deprotonation of the 3-keto-5-aminohexanoate substrate, nucleophilic addition onto an incoming acetyl-CoA, intramolecular transfer of the CoA moiety, and final retro-Claisen reaction leading to acetoacetate and 3-aminobutyryl-CoA. This model also accounts for earlier observations showing the origin of carbon atoms in the products, as well as the absence of detection of any covalent acyl-enzyme intermediate. Kce is the first representative of a large family of prokaryotic hypothetical proteins, currently annotated as the "domain of unknown function" DUF849.

Dates and versions

pasteur-03137933 , version 1 (10-02-2021)

Identifiers

Cite

Marco Bellinzoni, Karine Bastard, Alain Perret, Anne Zaparucha, Nadia Perchat, et al.. 3-Keto-5-aminohexanoate cleavage enzyme: a common fold for an uncommon Claisen-type condensation. Journal of Biological Chemistry, 2011, 286 (31), pp.27399-27405. ⟨10.1074/jbc.M111.253260⟩. ⟨pasteur-03137933⟩
42 View
0 Download

Altmetric

Share

Gmail Facebook X LinkedIn More