{PDOC51707}
{PS51707; CYTH}
{BEGIN}
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* CYTH domain profile *
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The CyaB  like  adenylyl  cyclase  and  the mammalian thiamine triphosphatases
(ThTPases) define  a  superfamily  of catalytic domains called the CYTH (CyaB,
thiamine triphosphatase)  domain that is present in all three superkingdoms of
life. CYTH  domains  are  likely to be domains specialized to bind nucleotides
and other organic phosphates [1].

The catalytic  core  of  the CYTH domain is predicted to contain an alpha+beta
scaffold with 6 conserved beta-strands and 6 conserved alpha-helices. The CYTH
domains contains  several  nearly  universally conserved charged residues that
are likely  to  form the active site. The most prominent of these are an EXEXK
motif associated with strand-1 of the domain, two basic residues in helix-2, a
K at the end of strand 3, an E in strand 4, a basic residue in helix-4, a D at
the end  of  strand 5 and two acidic residues (typically glutamates) in strand
6. The  presence of around 6 conserved acidic positions in the majority of the
CYTH domains  suggests  that it coordinates two divalent metal ions. Both CyaB
and ThTPase  have  been  shown  to  require  Mg(2+)  ions for their nucleotide
cyclase and  phosphatase  activities. The four conserved basic residues in the
CYTH domain  are  most  probably  involved  in the binding of acidic phosphate
moieties of  their  substrates. The conservation of these two sets of residues
in the  majority  of CYTH domains suggests that most members of this group are
likely to  possess  an activity dependent on two metal ions, with a preference
for nucleotides  or related phosphate-moiety -bearing substrates. The proposed
biochemical activity,  and the arrangement of predicted strands in the primary
structure of  the  CYTH domain imply that they may adopt a barrel or sandwich-
like configuration,  with  metal  ions and the substrates bound in the central
cavity [1].

The profile we developed covers the entire CYTH domain.

-Sequences known to belong to this class detected by the profile: ALL.
-Other sequence(s) detected in Swiss-Prot: NONE.
-Last update: February 2014 / First entry.

[ 1] Iyer L.M., Aravind L.
     "The catalytic domains of thiamine triphosphatase and CyaB-like
     adenylyl cyclase define a novel superfamily of domains that bind
     organic phosphates."
     BMC Genomics 3:33-33(2002).
     PubMed=12456267

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