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CATH Superfamily 3.40.50.300

P-loop containing nucleotide triphosphate hydrolases

The name of this superfamily has been modified since the most recent official CATH+ release (v4_2_0). At the point of the last release, this superfamily was named:

"
P-loop containing nucleotide triphosphate hydrolases
".

Functional Families

Overview of the Structural Clusters (SC) and Functional Families within this CATH Superfamily. Clusters with a representative structure are represented by a filled circle.
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FunFam 231153: Ras-related protein Rab-4B

There are 5 EC terms in this cluster

Please note: EC annotations are assigned to the full protein sequence rather than individual protein domains. Since a given protein can contain multiple domains, it is possible that some of the annotations below come from additional domains that occur in the same protein, but have been classified elsewhere in CATH.

Note: The search results have been sorted with the annotations that are found most frequently at the top of the list. The results can be filtered by typing text into the search box at the top of the table.

EC Term Annotations Evidence
Protein-synthesizing GTPase. [EC: 3.6.5.3]
GTP + H(2)O = GDP + phosphate.
  • This enzyme comprises a family of proteins involved in prokaryotic as well as eukaryotic protein synthesis.
  • In the initiation factor complex, it is IF-2b (98 kDa) that binds GTP and subsequently hydrolyzes it in prokaryotes.
  • In eukaryotes, it is eIF-2 (150 kDa) that binds GTP.
  • In the elongation phase, the GTP-hydrolyzing proteins are the EF-Tu polypeptide of the prokaryotic transfer factor (43 kDa), the eukaryotic elongation factor EF-1-alpha (53 kDa), the prokaryotic EF-G (77 kDa), the eukaryotic EF-2 (70-110 kDa) and the signal recognition particle that play a role in endoplasmic reticulum protein synthesis (325 kDa).
  • EF-Tu and EF-1-alpha catalyze binding of aminoacyl-tRNA to the ribosomal A-site, while EF-G and EF-2 catalyze the translocation of peptidyl-tRNA from the A-site to the P-site.
  • GTPase activity is also involved in polypeptide release from the ribosome with the aid of the pRFs and eRFs.
  • Formerly EC 3.6.1.48.
 2 E3TC90 E3TEK2
Small monomeric GTPase. [EC: 3.6.5.2]
GTP + H(2)O = GDP + phosphate.
  • A family of about 50 enzymes with a molecular mass of 21 kDa that are distantly related to the alpha-subunit of EC 3.6.1.46.
  • Involved in cell-growth regulation (Ras subfamily), membrane vesicle traffic and uncoating (Rab and ARF subfamilies), nuclear protein import (Ran subfamily) and organization of the cytoskeleton (Rho and Rac subfamilies).
  • Formerly EC 3.6.1.47.
 2 E3TC90 E3TEK2
Heterotrimeric G-protein GTPase. [EC: 3.6.5.1]
GTP + H(2)O = GDP + phosphate.
  • This group comprises GTP-hydrolyzing systems, where GTP and GDP alternate in binding.
  • This group includes stimulatory and inhibitory G-proteins such as G(s), G(i), G(o) and G(olf), targeting adenylate cyclase and/or K(+) and Ca(2+) channels; G(q) stimulating phospholipase C; transducin activating cGMP phosphodiesterase; gustducin activating cAMP phosphodiesterase.
  • G(olf) is instrumental in odor perception, transducin in vision and gustducin in taste recognition.
  • At least 16 different alpha subunits (39-52 kDa), 5 beta subunits (36 kDa) and 12 gamma subunits (6-9 kDa) are known.
  • Formerly EC 3.6.1.46.
 2 E3TC90 E3TEK2
Signal-recognition-particle GTPase. [EC: 3.6.5.4]
GTP + H(2)O = GDP + phosphate.
  • Activity is associated with the signal-recognition particle (a protein- and RNA-containing structure involved in endoplasmic- reticulum-associated protein synthesis).
  • Formerly EC 3.6.1.49.
 2 E3TC90 E3TEK2
Sphingomyelin phosphodiesterase. [EC: 3.1.4.12]
Sphingomyelin + H(2)O = N-acylsphingosine + phosphocholine.
  • Has very little activity on phosphatidylcholine.
 1 B7Q2W4