{PDOC51714}
{PS51714; G_BMS1}
{BEGIN}
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* Bms1-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.

Bms1p and  Tsr1p  represent  a  new  family  of  factors required for ribosome
biogenesis. They  are  each  independently  required for 40S ribosomal subunit
biogenesis. Bms1p,  a  protein  required  for pre-rRNA processing, contains an
evolutionarily conserved  G  domain  with  five  conserved  polypeptide  loops
designated G1 through G5, which form contact sites with the guanine nucleotide
or coordinate the Mg(2+) ion. Sequences ressembling G1 (consensus [GA]-x(4)-G-
K-[ST]; also  known as a P-loop), G4 (consensus [NT]-K-x-D), and G5 (consensus
S-[AG] are  present  in  all  Bms1 proteins, and either fully conform with the
consensus or contain, at most, single conservative substitutions. The G2 motif
(consensus G-P-[IV]-T)  contains  a  T residue involved in the coordination of
the Mg(2+)  required  for  GTP  hydrolysis.  The  G3  motif  diverges from the
consensus found  in  G  proteins, D-x(2)-G; however, the D residue is replaced
with the  conserved  E  residue.  In contrast, Tsr1p lacks a P-loop and is not
predicted to  bind  GTP.  It  functions  at  a  later  step  of  40S  ribosome
production, possibly  in  assembly and/or export of 43S pre-ribosomal subunits
to the cytosol [1,2,3].

The Bms1-type G domain has a small GTPase-like fold (see <PDB:5IW7>) [1].

The profile we developed covers the entire Bms1-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: May 2020 / Profile and text revised.

[ 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] Wegierski T., Billy E., Nasr F., Filipowicz W.
     "Bms1p, a G-domain-containing protein, associates with Rcl1p and is
     required for 18S rRNA biogenesis in yeast."
     RNA 7:1254-1267(2001).
     PubMed=11565748
[ 3] Gelperin D., Horton L., Beckman J., Hensold J., Lemmon S.K.
     "Bms1p, a novel GTP-binding protein, and the related Tsr1p are
     required for distinct steps of 40S ribosome biogenesis in yeast."
     RNA 7:1268-1283(2001).
     PubMed=11565749
[ 4] McCaughan U.M., Jayachandran U., Shchepachev V., Chen Z.A.,
     Rappsilber J., Tollervey D., Cook A.G.
     "Pre-40S ribosome biogenesis factor Tsr1 is an inactive structural
     mimic of translational GTPases."
     Nat. Commun. 7:11789-11789(2016).
     PubMed=27250689; DOI=10.1038/ncomms11789

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