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* Glycine radical signature *
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Escherichi coli  pyruvate formate-lyase  (EC 2.3.1.54)  (gene pfl)  is  a  key
enzyme of anaerobic  glucose metabolism,  it  converts  pyruvate  and CoA into
acetyl-CoA and pyruvate.  This enzyme  is  posttranslationally interconverted,
under anaerobic conditions,  from an inactive to an active form that carries a
stable radical localized to a specific glycine at the C-terminal region of the
polypeptidic chain [1].

Such a glycine radical seems [2]  also to be present in Escherichia coli (gene
nrdD) and bacteriophage T4 (gene sunY)  anaerobic  ribonucleoside-triphosphate
reductase (EC 1.17.4.2). An Escherichia coli hypothetical protein (yijL) which
is highly similar to pfl could also contain such a radical.

These proteins share a conserved region  centered around the glycine which, in
pfl, is  known to  bear the free radical.  We  use this region has a signature
pattern.

-Consensus pattern: [STIV]-x-R-[VT]-[CSA]-G-Y-x-[GAV]
                    [G carries the radical]
-Sequences known to belong to this class detected by the pattern: ALL.
-Other sequence(s) detected in SWISS-PROT: a phage T4 hypothetical protein and
 a fragment from a Serratia liquefaciens hypothetical protein which could be a
 member of this family.
-Last update: October 1993 / First entry.

[ 1] Wagner A.F.V., Frey M., Neugebauer F.A., Schaefer W., Knappe J.
     Proc. Natl. Acad. Sci. U.S.A. 89:996-1000(1992).
[ 2] Sun X., Harder J., Krook M., Joernvall H., Sjoeberg B.-M., Reichard P.
     Proc. Natl. Acad. Sci. U.S.A. 90:577-581(1993).