*********************************************************
* Transcriptional antiterminators bglG family signature *
*********************************************************

Escherichia coli bglG  protein  mediates  the positive regulation of the beta-
glucoside (bgl) operon  by  functioning  as a  transcriptional antiterminator.
bglG is a RNA-binding protein that recognizes a specific sequence located just
upstream of two termination sites within the operon.   The activity of bglG is
supressed by its phosphorylation [2] by bglF (EII-bgl), the  permease from the
beta-glucoside PTS system.

BglG is highly similar to the following proteins, which  also  probably act as
transcriptional antiterminators:

 - arbG  from  Erwinia chrysanthemi [3], also  involved in the regulation of a
   beta-glucoside operon. ArbG is probably phosphorylated by arbF (EII-bgl).
 - sacT from Bacillus subtilis,  which regulates the expression of the sucrose
   operon (sacPA). SacT is probably phosphorylated by sacP (EII-scr).
 - sacY from  Bacillus  subtilis,   which  regulates  the  expression  of  the
   levansucrase operon (sacBX).  SacY is  probably  phosphorylated by the sacX
   protein.
 - levR from Bacillus subtilis, which regulates the expression of the levanase
   operon (levDEFG and sacC). LevR is  composed  of  two domains: a N-terminal
   section that contains a  sigma-54 factor interaction ATP-binding domain and
   a C-terminal  bglG-like  domain.  LevR  could  be phosphorylated by levD or
   levE.

As a signature pattern for these proteins, we selected a conserved region that
includes a conserved histidine that could be the site of phosphorylation.

-Consensus pattern: [ST]-x-H-x(2)-[FA](2)-[LIVM]-x-R-x(2)-[QN]
                    [H could be phosphorylated]
-Sequences known to belong to this class detected by the pattern: ALL.
-Other sequence(s) detected in SWISS-PROT: Escherichia coli feoB.
-Last update: June 1994 / Text revised.

[ 1] Houman F., Diaz-Torre M.R., Wright A.
     Cell 62:1153-1163(1990).
[ 2] Amster-Choder O., Wright A.
     Science 249:540-542(1990).
[ 3] El Hassouni M., Henrissat B., Chippaux M., Barras F.
     J. Bacteriol. 174:765-777(1992).