HflX-type guanine nucleotide-binding (G) domain (IPR030394)

Short name: G_HFLX_dom

Overlapping homologous superfamilies

Domain relationships



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 [PMID: 11916378, PMID: 19787775, PMID: 19824612].

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 [PMID: 19787775]. 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 [PMID: 19824612].

GO terms

Biological Process

No terms assigned in this category.

Molecular Function

GO:0005525 GTP binding

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
PROSITE profiles