{PDOC00703}
{PS51147; PFTA}
{BEGIN}
***********************************************************
* Protein prenyltransferases alpha subunit repeat profile *
***********************************************************

Protein  prenyltransferases  catalyze the transfer of an isoprenyl moiety to a
cysteine  at  or  near the C-terminus of several eukaryotic proteins. They are
heterodimeric enzymes consisting of alpha and beta subunits. The alpha subunit
is  thought  to  participate in a stable complex with the isoprenyl substrate;
the beta subunit binds the peptide substrate. There are three types of protein
prenyltransferases.  The alpha subunits of two types, i.e. farnesyltransferase
and  geranylgeranyltransferase  I  are  encoded  by the same gene, FNTA. These
proteins  bind  the  same  motif  (the  CaaX box) around the cysteine in their
substrates.  The  third  type,  geranylgeranyl  transferase  type  II  (Rab GG
transferase) recognizes a different, non-CaaX motif [1].

Both  the  alpha  and  beta subunit show repetitive sequence motifs [2]. These
repeats have distinct structural and functional implications and are unrelated
to  each other. The conserved domain of the alpha subunit consists of about 35
amino  acids  and  is  repeated  five  times.  The domain folds into a pair of
antiparallel  alpha  helices,  which are packed in a parallel arrangement with
adjacent  domains  in  a  superhelical  pattern  (see <PDB:1TN6>). A conserved
tryptophan  in the fourth position of the second helix interacts with both the
first helix and the neighboring helix of the next repeat [3].

Two types of protein prenyltransferase alpha subunits are known:

 - Farnesyltransferase/geranylgeranyltransferase    type-1    subunit    alpha
   (EC 2.5.1.58) (EC 2.5.1.59).
 - Geranylgeranyl transferase type-2 subunit alpha (EC 2.5.1.60).

The  profile  we  developed covers the entire protein prenyltransferases alpha
subunit repeat.

-Sequences known to belong to this class detected by the profile: ALL.
-Other sequence(s) detected in Swiss-Prot: NONE.

-Last update: October 2005 / Pattern removed, profile added and text revised.

[ 1] Maurer-Stroh S., Washietl S., Eisenhaber F.
     "Protein prenyltransferases."
     Genome Biol. 4:212-212(2003).
     PubMed=12702202
[ 2] Boguski M.S., Murray A.W., Powers S.
     "Novel repetitive sequence motifs in the alpha and beta subunits of
     prenyl-protein transferases and homology of the alpha subunit to the
     MAD2 gene product of yeast."
     New Biol. 4:408-411(1992).
     PubMed=1622936
[ 3] Zhang H., Grishin N.V.
     "The alpha-subunit of protein prenyltransferases is a member of the
     tetratricopeptide repeat family."
     Protein Sci. 8:1658-1667(1999).
     PubMed=10452610
{END}