Description | This entry represents the HflX-type G domain.The P-loop 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 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 [ ]. 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 []. | Name | HflX-type guanine nucleotide-binding (G) domain |
Short Name | G_HFLX_dom | Type | Domain |