{PDOC00706}
{PS00908; MR_MLE_1}
{PS00909; MR_MLE_2}
{BEGIN}
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* Mandelate racemase / muconate lactonizing enzyme family signatures *
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Mandelate racemase   (EC 5.1.2.2)   (MR)  and   muconate  lactonizing   enzyme
(EC 5.5.1.1)  (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 5.5.1.7).
 - 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).

-Consensus pattern: [AT]-x-[SAGCN]-[SAGC]-[LIVM]-[DEQ]-x-A-[LA]-x-[DE]-[LIA]-
                    x-[GA]-[KRQ]-x(4)-[PSA]-[LIV]-x(2)-L-[LIVMF]-G
-Sequences known to belong to this class detected by the pattern: ALL.
-Other sequence(s) detected in Swiss-Prot: NONE.

-Consensus pattern: [LIVF]-x(2)-D-x-[NH]-x(7)-[ACL]-x(6)-[LIVMF]-x(7)-[LIVM]-
                    E-[DENQ]-P
                    [D and E bind a divalent metal ion]
-Sequences known to belong to this class detected by the pattern: ALL.
-Other sequence(s) detected in Swiss-Prot: NONE.

-Last update: December 2001 / Patterns and text revised.

[ 1] Neidhart D.J., Kenyon G.L., Gerlt J.A., Petsko G.A.
     "Mandelate racemase and muconate lactonizing enzyme are
     mechanistically distinct and structurally homologous."
     Nature 347:692-694(1990).
     PubMed=2215699; DOI=10.1038/347692a0
[ 2] Petsko G.A., Kenyon G.L., Gerlt J.A., Ringe D., Kozarich J.W.
     "On the origin of enzymatic species."
     Trends Biochem. Sci. 18:372-376(1993).
     PubMed=8256284
[ 3] Huisman G.W., Kolter R.
     "Sensing starvation: a homoserine lactone--dependent signaling pathway
     in Escherichia coli."
     Science 265:537-539(1994).
     PubMed=7545940
[ 4] Schneider D., Aigle B., Leblond P., Simonet J.M., Decaris B.
     "Analysis of genome instability in Streptomyces ambofaciens."
     J. Gen. Microbiol. 139:2559-2567(1993).
     PubMed=8277241

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