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* DNA polymerase family B signature *
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Replicative  DNA polymerases (EC  2.7.7.7) are the key enzymes  catalyzing the
accurate  replication of DNA.   They require either a small RNA molecule or  a
protein as a primer for the de novo synthesis of a DNA chain.  On the basis of
sequence similarities  a number of DNA polymerases have  been grouped together
[1 to 7]  under the designation of DNA polymerase family B.    The polymerases
that belong to this family are:

 - Higher eukaryotes polymerases alpha.
 - Higher eukaryotes polymerases delta.
 - Yeast polymerase  I/alpha (gene POL1),  polymerase II/epsilon  (gene POL2),
   polymerase III/delta (gene POL3), and polymerase REV3.
 - Escherichia coli polymerase II (gene dinA or polB).
 - Archaebacterial polymerases.
 - Polymerases of viruses from the herpesviridae family.
 - Polymerases from Adenoviruses.
 - Polymerases from Baculoviruses.
 - Polymerases from Chlorella viruses.
 - Polymerases from Poxviruses.
 - Bacteriophage T4 polymerase.
 - Podoviridae bacteriophages Phi-29, M2, and PZA polymerase.
 - Tectiviridae bacteriophage PRD1 polymerase.
 - Polymerases encoded  on mitochondrial linear  DNA plasmids in various fungi
   and plants  (Kluyveromyces lactis pGKL1 and pGKL2,  Agaricus bitorquis pEM,
   Ascobolus immersus pAI2,  Claviceps purpurea pCLK1,  Neurospora Kalilo  and
   Maranhar, maize S-1, etc).

Six regions of similarity (numbered from I to VI) are found in all or a subset
of the above polymerases.  The most conserved region  (I) includes a conserved
tetrapeptide  which  contains  two  aspartate residues.   The function of this
conserved region is not  yet known, however it has been suggested [3] that  it
may be involved in binding a magnesium ion.  We selected this conserved region
as a signature for this family of DNA polymerases.

-Consensus pattern: [YA]-[GLIVMSTAC]-D-T-D-[SG]-[LIVMFTC]-x-[LIVMSTAC]
-Sequences known to belong to this class detected by the pattern: ALL,  except
 for yeast polymerase II/epsilon and Agaricus bitorquis pEM.
-Other sequence(s) detected in SWISS-PROT: 3.
-Last update: June 1994 / Text revised.

[ 1] Jung G., Leavitt M.C., Hsieh J.-C., Ito J.
     Proc. Natl. Acad. Sci. U.S.A. 84:8287-8291(1987).
[ 2] Bernad A., Zaballos A., Salas M., Blanco L.
     EMBO J. 6:4219-4225(1987).
[ 3] Argos P.
     Nucleic Acids Res. 16:9909-9916(1988).
[ 4] Wang T.S.-F., Wong S.W., Korn D.
     FASEB J. 3:14-21(1989).
[ 5] Delarue M., Poch O., Todro N., Moras D., Argos P.
     Protein Eng. 3:461-467(1990).
[ 6] Ito J., Braithwaite D.K.
     Nucleic Acids Res. 19:4045-4057(1991).
[ 7] Braithwaite D.K., Ito J.
     Nucleic Acids Res. 21:787-802(1993).