|PROSITE documentation PDOC51705|
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 [1,2,3].
Within the translation factor-related (TRAFAC) class of P-loop GTPases, the HflX-type is a widely distributed family of GTPases that interact with the large ribosomal subunit. The broad phylogenetic distribution pattern of HflX GTPases in Bacteria, Archaea, and Eukaryotes (including human) suggests a basic cellular function for this protein family.
The HflX-type G domain is composed of six β-strands and five α-helices (see <PDB:2QTF>) . It consists of the following conserved sequence motifs: the G1 motif (or P-loop), consensus GX4GK(S/T), which is responsible for interacting with the α and β-phosphates of nucleotide di- and triphosphates; the G2 variable effector loop (DXnT); the G3 motif (DX2G), which interacts with the γ-phosphate of nucleotide triphosphates; and the G4 motif (NKXD), which conveys specificity for guanine nucleotides through hydrogen bonding to the base .
The profile we developed covers the entire HflX-type G domain.Last update:
February 2014 / First entry.
PROSITE method (with tools and information) covered by this documentation:
|1||Authors||Leipe D.D. Wolf Y.I. Koonin E.V. Aravind L.|
|Title||Classification and evolution of P-loop GTPases and related ATPases.|
|Source||J. Mol. Biol. 317:41-72(2002).|
|2||Authors||Wu H. Sun L. Blombach F. Brouns S.J.J Snijders A.P.L: Lorenzen K. van den Heuvel R.H.H. Heck A.J.R. Fu S. Li X. Zhang X.C. Rao Z. van der Oost J.|
|Title||Structure of the ribosome associating GTPase HflX.|
|3||Authors||Shields M.J. Fischer J.J. Wieden H.-J.|
|Title||Toward understanding the function of the universally conserved GTPase HflX from Escherichia coli: a kinetic approach.|