{PDOC51710}
{PS51710; G_OBG}
{BEGIN}
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* OBG-type guanine nucleotide-binding (G) domain profile *
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The P-loop  (see  <PDOC00017>)  guanosine  triphosphatases (GTPases) control a
multitude of  biological  processes, ranging from cell division, cell cycling,
and signal  transduction,  to ribosome assembly and protein synthesis. GTPases
exert their  control  by interchanging between an inactive GDP-bound state and
an active  GTP-bound  state,  thereby acting as molecular switches. The common
denominator of  GTPases is the highly conserved guanine nucleotide-binding (G)
domain that is responsible for binding and hydrolysis of guanine nucleotides.

Within the  translation  factor-related  (TRAFAC) class of P-loop GTPases, the
OBG family  comprises  a  group  of high-molecular mass GTPases conserved from
bacteria to eukaryotes. The OBG family consists of [1]:

 - Obg from bacteria and eukaryotes [2,3].
 - DRG  from  eukaryotes  and  archaea.  DRG proteins may regulate fundamental
   cellular processes through RNA binding [4].
 - Nog1  from  eukaryotes  and  archaea. It is involved in the assembly of the
   large ribosomal subunit.
 - Yyaf/YchF  from bacteria and eukaryotes. It consists of a central G domain,
   flanked by a coiled-coil domain and a TGS (ThrRS, GTPase, SpoT) domain (see
   <PDOC51880>). Members   of  this  subfamily  bind  and  hydolyze  ATP  more
   efficiently than GTP [5,6].
 - Ygr210 from archaea and fungi.

The OBG-type G domain has a mononucleotide binding fold typical for the P-loop
NTPases. A six-stranded mostly parallel beta-sheet is flanked by alpha-helices
on both   sides   (see  <PDB:1JAL>).  The  OBG-type  G  domain  contains  five
characteristic sequence  motifs,  termed G1-G5, involved in nucleotide binding
and hydrolysis.  The  G1/Walker A motif (GXXXXGK(S/T)), also referred to as P-
loop, helps  to  position the triphosphate moiety of the bound nucleotide. The
G2 (X(T/S)X) and G3/Walker B (hhhDXXG) motifs are involved in the coordination
of a  Mg(2)+  ion  that  is  required  for  nucleotide binding and hydrolysis.
Specificity in  nucleotide  binding  is conferred by the G4 motif, which has a
(N/T)KXD signature  in guanine nucleotide binding P-loop NTPases. The G5 motif
((T/G)(C/S)A) supports guanine base recognition [2,3,5,6].

The profile we developed covers the entire OBG-type G domain.

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

[ 1] Leipe D.D., Wolf Y.I., Koonin E.V., Aravind L.
     "Classification and evolution of P-loop GTPases and related ATPases."
     J. Mol. Biol. 317:41-72(2002).
     PubMed=11916378; DOI=10.1006/jmbi.2001.5378
[ 2] Buglino J., Shen V., Hakimian P., Lima C.D.
     "Structural and biochemical analysis of the Obg GTP binding protein."
     Structure 10:1581-1592(2002).
     PubMed=12429099
[ 3] Kukimoto-Niino M., Murayama K., Inoue M., Terada T., Tame J.R.H.,
     Kuramitsu S., Shirouzu M., Yokoyama S.
     "Crystal structure of the GTP-binding protein Obg from Thermus
     thermophilus HB8."
     J. Mol. Biol. 337:761-770(2004).
     PubMed=15019792; DOI=10.1016/j.jmb.2004.01.047
[ 4] Ishikawa K., Azuma S., Ikawa S., Morishita Y., Gohda J., Akiyama T.,
     Semba K., Inoue J.i.
     "Cloning and characterization of Xenopus laevis drg2, a member of the
     developmentally regulated GTP-binding protein subfamily."
     Gene 322:105-112(2003).
     PubMed=14644502
[ 5] Teplyakov A., Obmolova G., Chu S.Y., Toedt J., Eisenstein E.,
     Howard A.J., Gilliland G.L.
     "Crystal structure of the YchF protein reveals binding sites for GTP
     and nucleic acid."
     J. Bacteriol. 185:4031-4037(2003).
     PubMed=12837776
[ 6] Koller-Eichhorn R., Marquardt T., Gail R., Wittinghofer A.,
     Kostrewa D., Kutay U., Kambach C.
     "Human OLA1 defines an ATPase subfamily in the Obg family of
     GTP-binding proteins."
     J. Biol. Chem. 282:19928-19937(2007).
     PubMed=17430889; DOI=10.1074/jbc.M700541200

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