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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 628018: Guanine nucleotide-binding protein subunit alpha

There are 8 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
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.
 12 B2Z3E2 B3KYI8 B3KYI9 B3KYJ0 E3TFU4 F7W3U7 Q6QM14 Q6QM15 Q6QM16 Q6QM17
(2 more...)
DGTPase. [EC: 3.1.5.1]
dGTP + H(2)O = deoxyguanosine + triphosphate.
  • Also acts on GTP.
 8 A0A0F4YJP4 A0A100IIH6 A0A1L9NP10 A0A1L9UPM5 A0A1M3TNM5 A2QRI2 G3YHH3 G7XNI1
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.
 2 A0A161MMM8 A0A170ZZQ9
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.
 1 E3TFU4
Glycogen phosphorylase. [EC: 2.4.1.1]
((1->4)-alpha-D-glucosyl)(n) + phosphate = ((1->4)-alpha-D-glucosyl)(n-1) + alpha-D-glucose 1-phosphate.
  • This entry covers several enzymes from different sources that act in vivo on different forms of (1->4)-alpha-D-glucans.
  • Some of these enzymes catalyze the first step in the degradation of large branched glycan polymers - the phosphorolytic cleavage of alpha-1,4-glucosidic bonds from the non-reducing ends of linear poly(1->4)-alpha-D-glucosyl chains within the polymers.
  • The enzyme stops when it reaches the fourth residue away from an alpha-1,6 branching point, leaving a highly branched core known as a limit dextrin.
  • The description (accepted name) of the enzyme should be modified for each specific instance by substituting 'glycogen' with the name of the natural substrate, e.g. maltodextrin phosphorylase, starch phosphorylase, etc.
 1 A0A1B8AG69
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.
 1 E3TFU4
Beta-glucosidase. [EC: 3.2.1.21]
Hydrolysis of terminal, non-reducing beta-D-glucosyl residues with release of beta-D-glucose.
  • Wide specificity for beta-D-glucosides.
  • Some examples also hydrolyze one or more of the following: beta-D- galactosides, alpha-L-arabinosides, beta-D-xylosides and beta-D- fucosides.
 1 A0A179GDT9
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.
 1 E3TFU4
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