Bms1/Tsr1-type G domain (IPR030387)

Short name: G_Bms1/Tsr1_dom

Overlapping homologous superfamilies


Domain relationships



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 guanine nucleotide-binding (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 resembling 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 [PMID: 11916378, PMID: 11565748, PMID: 11565749].

This entry represents a domain found in Bms1 and Tsr1, and includes cases, such as Tsr1, where it may not function as a guanine nucleotide-binding domain.

Contributing signatures

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