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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 632028: GTP binding protein 1

There are 3 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 G4RKS9 H6Q985
Nucleoside-triphosphate phosphatase. [EC: 3.6.1.15]
NTP + H(2)O = NDP + phosphate.
  • The enzyme is found in eukaryotes and thermophilic bacteria, but appears to be absent from mesophilic bacteria.
  • Also hydrolyzes nucleoside diphosphates, thiamine diphosphate and FAD.
  • The enzyme from the plant Pisum sativum (garden pea) is regulated by calmodulin.
 1 A0A161MIK5
2-methoxy-6-polyprenyl-1,4-benzoquinol methylase. [EC: 2.1.1.201]
S-adenosyl-L-methionine + 2-methoxy-6-all-trans-polyprenyl-1,4- benzoquinol = S-adenosyl-L-homocysteine + 6-methoxy-3-methyl-2-all-trans- polyprenyl-1,4-benzoquinol.
  • This enzyme is involved in ubiquinone biosynthesis.
  • Ubiquinones from different organisms have a different number of prenyl units (for example, ubiquinone-6 in Saccharomyces, ubiquinone- 9 in rat and ubiquinone-10 in human), and thus the natural substrate for the enzymes from different organisms has a different number of prenyl units.
  • However, the enzyme usually shows a low degree of specificity regarding the number of prenyl units.
  • For example, when the COQ5 gene from Saccharomyces cerevisiae is introduced into Escherichia coli, it complements the respiratory deficiency of an ubiE mutant.
  • The bifunctional enzyme from E.coli also catalyzes the methylation of demethylmenaquinol-8 (this activity is classified as EC 2.1.1.163).
 1 A0A131ZVI6