{PDOC51705} {PS51705; G_HFLX} {BEGIN} *********************************************************** * HflX-type guanine nucleotide-binding (G) domain profile * *********************************************************** The P-loop (see ) 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 beta-strands and five alpha-helices (see ) [2]. 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 alpha and beta-phosphates of nucleotide di- and triphosphates; the G2 variable effector loop (DXnT); the G3 motif (DX2G), which interacts with the gamma-phosphate of nucleotide triphosphates; and the G4 motif (NKXD), which conveys specificity for guanine nucleotides through hydrogen bonding to the base [3]. The profile we developed covers the entire HflX-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: February 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] 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. "Structure of the ribosome associating GTPase HflX." Proteins 78:705-713(2010). PubMed=19787775; DOI=10.1002/prot.22599 [ 3] Shields M.J., Fischer J.J., Wieden H.-J. "Toward understanding the function of the universally conserved GTPase HflX from Escherichia coli: a kinetic approach." Biochemistry 48:10793-10802(2009). PubMed=19824612; DOI=10.1021/bi901074h -------------------------------------------------------------------------------- PROSITE is copyrighted by the SIB Swiss Institute of Bioinformatics and distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives (CC BY-NC-ND 4.0) License, see https://prosite.expasy.org/prosite_license.html -------------------------------------------------------------------------------- {END}