The name of this superfamily has been modified since the most recent official CATH+ release (v4_3_0). At the point of the last release, this superfamily was: waiting to be named.

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.

Superfamily: Aminohydrolase, N-terminal nucleophile (Ntn) domain, beta-sheet knob region

Amidohydrolases include glutamine PRPP amidotransferases (GATs), penicillin acylases/amidases (such as penicillin G acylases or PGAs and penicillin V acylases or PVAs), the 20S proteasome beta subunit (PRO), class II glutamine amidotransferases, glycosyl asparaginases (GAs), and also cephalosporin acylases, such as CAD, a class I cephalosporin acylase. The importance of Ntn hydrolases resides in the biosynthesis of beta-lactam antibiotics such as cephalosporin and penicillin. All enzymes in this superfamily share an unusual fold in which the nucleophile and other catalytic groups occupy equivalent sites. This fold provides both the capacity for nucleophilic attack and the possibility of autocatalytic processing. Posttranslational autoproteolysis is a mechanism used to activate many proteins via self-catalysed peptide bond rearrangements, which play an essential role in a wide variety of biological processes. They include activation cascades such as blood coagulation and fibrinolysis, cell death, embryonic development, protein targeting and degradation, viral protein processing, and zymogen activation.

A well-characterised enzyme containing this domain is CAD, a cephalosporin acylase from Pseudomonas diminuta. It consists of an alpha-subunit with 169 residues and a beta-subunit with 520 residues. The enzyme is described as a bowl-shaped molecule with two knobs attached to the bowl, facing each other. The A-knob contains mostly alpha-helices, whereas the B-knob contains mostly beta-sheets. The B-knob region is made up of seven beta-strands which form a distorted beta-barrel-like domain. This superfamily entry comprises structural domains similar to the beta-sheet B-knob region described in CAD.

Pfam clan [PfamClan:CL0052], Pfam family PFAM:PF01804, INTERPRO:IPR029055,PMID:7477383,PMID:11601852,PMID:11080627,PMID:16446446,PMID:23373797

GO Diversity

Unique GO annotations
11 Unique GO terms

EC Diversity

Unique EC annotations
3 Unique EC terms

Species Diversity

Unique species annotations
4767 Unique species

Sequence/Structure Diversity

Overview of the sequence / structure diversity of this superfamily compared to other superfamilies in CATH. Click on the chart to view the data in more detail.

Superfamily Summary

A general summary of information for this superfamily.
Domains: 99
Domain clusters (>95% seq id): 9
Domain clusters (>35% seq id): 5
Unique PDBs: 76
Structural Clusters (5A): 1
Structural Clusters (9A): 1
FunFam Clusters: 4
Unique EC: 3
Unique GO: 11
Unique Species: 4767