{PDOC51531}
{PS51531; FV_PR}
{BEGIN}
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* Foamy virus protease (FV PR) domain profile *
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Spumaviruses or  foamy  viruses (FVs) are a group of complex retroviruses that
have been  isolated  from  a  number  of animal species and are believed to be
apathogenic in  their  animal host [E1]. FVs express a pol-specific transcript
that codes  for  a Pol polyprotein that consists of the protease (PR), reverse
transcriptase, robonuclease  H  ,  and  the integrase domains. Retrovriral PRs
belong to  the family of aspartic proteases and are active as homodimers, with
the active   site   triplets   (Asp-Thr/Ser-Gly;   D-T/S-G)  from  both  chain
contributing to the symetric active site of the enzyme. Transient FV PR domain
homodimers are  formed  under native condition but are only present as a minor
transient species,   which   is   not   detectable   by  traditional  methods.
Dimerization of  FV  RT  might  be  triggered  by additional viral or cellular
factors [1,2,3,4].  The  FV  PR  domain forms peptidase family A9 (spumapepsin
family) [E2].

The FV  PR  domain  consists  of  seven  beta-strands  and a helical turn (see
<pdb:2JYS>). The  beta-strands  form  a closed barrel-like beta-sheet with the
strand order  beta1-beta2-beta7-beta3-beta6-beta5-beta1. The strands beta1 and
beta7 are  arranged  in  parallel,  while all other strands are arranged in an
anti-parallel manner [3].

The profile we developed covers the entire FV PR domain.

-Sequences known to belong to this class detected by the profile: ALL.
-Other sequence(s) detected in Swiss-Prot: NONE.
-Last update: March 2011 / First entry.

[ 1] Konvalinka J., Loechelt M., Zentgraf H., Fluegel R.M., Kraeusslich H.-G.
     "Active foamy virus proteinase is essential for virus infectivity but
     not for formation of a Pol polyprotein."
     J. Virol. 69:7264-7268(1995).
     PubMed=7474150
[ 2] Pfrepper K.-I., Rackwitz H.-R., Schnoelzer M., Heid H., Loechelt M.,
     Fluegel R.M.
     "Molecular characterization of proteolytic processing of the Pol
     proteins of human foamy virus reveals novel features of the viral
     protease."
     J. Virol. 72:7648-7652(1998).
     PubMed=9696869
[ 3] Hartl M.J., Woehrl B.M., Roesch P., Schweimer K.
     "The solution structure of the simian foamy virus protease reveals a
     monomeric protein."
     J. Mol. Biol. 381:141-149(2008).
     PubMed=18597783; DOI=10.1016/j.jmb.2008.05.064
[ 4] Hartl M.J., Schweimer K., Reger M.H., Schwarzinger S., Bodem J.,
     Rosch P., Wohrl B.M.
     "Formation of transient dimers by a retroviral protease."
     Biochem. J. 427:197-203(2010).
     PubMed=20136635; DOI=10.1042/BJ20091451
[E1] https://viralzone.expasy.org/10?outline=all_by_protein
[E2] https://www.ebi.ac.uk/merops/cgi-bin/famsum?family=A9

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