PROSITE documentation PDOC00706 [for PROSITE entry PS00909]
Mandelate racemase / muconate lactonizing enzyme family signatures


Mandelate racemase (EC (MR) and muconate lactonizing enzyme (EC (MLE) are two bacterial enzymes involved in aromatic acid catabolism. They catalyze mechanistically distinct reactions yet they are related at the level of their primary, quaternary (homooctamer) and tertiary structures [1,2].

A number of other proteins also seem to be evolutionary related to these two enzymes. These are:

  • The various plasmid-encoded chloromuconate cycloisomerases (EC
  • Escherichia coli protein rspA [3], rspA seems to be involved in the degradation of homoserine lactone (HSL) or of one of its metabolite.
  • Escherichia coli hypothetical protein ycjG.
  • Escherichia coli hypothetical protein ydaW.
  • Escherichia coli hypothetical protein yidU.
  • A hypothetical protein from Streptomyces ambofaciens [4].

We developed two signature patterns for these enzymes; both contain conserved acidic residues. The second pattern contains an aspartate and a glutamate which are ligands for either a magnesium ion (in MR) or a manganese ion (in MLE).

Last update:

December 2001 / Patterns and text revised.


Technical section

PROSITE methods (with tools and information) covered by this documentation:

MR_MLE_2, PS00909; Mandelate racemase / muconate lactonizing enzyme family signature 2  (PATTERN)

MR_MLE_1, PS00908; Mandelate racemase / muconate lactonizing enzyme family signature 1  (PATTERN)


1AuthorsNeidhart D.J. Kenyon G.L. Gerlt J.A. Petsko G.A.
TitleMandelate racemase and muconate lactonizing enzyme are mechanistically distinct and structurally homologous.
SourceNature 347:692-694(1990).
PubMed ID2215699

2AuthorsPetsko G.A. Kenyon G.L. Gerlt J.A. Ringe D. Kozarich J.W.
TitleOn the origin of enzymatic species.
SourceTrends Biochem. Sci. 18:372-376(1993).
PubMed ID8256284

3AuthorsHuisman G.W. Kolter R.
TitleSensing starvation: a homoserine lactone--dependent signaling pathway in Escherichia coli.
SourceScience 265:537-539(1994).
PubMed ID7545940

4AuthorsSchneider D. Aigle B. Leblond P. Simonet J.M. Decaris B.
TitleAnalysis of genome instability in Streptomyces ambofaciens.
SourceJ. Gen. Microbiol. 139:2559-2567(1993).
PubMed ID8277241

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