{PDOC00274}
{PS00302; IF5A_HYPUSINE}
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* Eukaryotic initiation factor 5A hypusine signature *
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Eukaryotic initiation factor 5A (eIF-5A) (formerly known as eIF-4D) [1,2] is a
small protein whose precise role in the initiation of protein synthesis is not
known. It appears to promote the formation of the first peptide bond.   eIF-5A
seems to be the  only  eukaryotic  protein  to  contain  an  hypusine residue.
Hypusine is  derived  from  lysine  by  the  post-translational  addition of a
butylamino group (from spermidine) to the epsilon-amino group of lysine.   The
hypusine group is essential to the function of eIF-5A.

A hypusine-containing  protein  has  been  found  in  archaebacteria  such  as
Sulfolobus acidocaldarius or Methanococcus jannaschii; this protein is  highly
similar to eIF-5A and could play a similar role in protein biosynthesis.

The signature we developed for eIF-5A is centered around the hypusine residue.

-Consensus pattern: [PT]-G-K-H-G-x-A-K
                    [The first K is modified to hypusine]
-Sequences known to belong to this class detected by the pattern: ALL.
-Other sequence(s) detected in Swiss-Prot: NONE.
-Last update: November 1997 / Pattern and text revised.

[ 1] Park M.H., Wolff E.C., Folk J.E.
     "Hypusine: its post-translational formation in eukaryotic initiation
     factor 5A and its potential role in cellular regulation."
     Biofactors 4:95-104(1993).
     PubMed=8347280
[ 2] Schnier J., Schwelberger H.G., Smit-McBride Z., Kang H.A., Hershey J.W.
     "Translation initiation factor 5A and its hypusine modification are
     essential for cell viability in the yeast Saccharomyces cerevisiae."
     Mol. Cell. Biol. 11:3105-3114(1991).
     PubMed=1903841

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