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: SPOUT methyltransferase, trefoil knot domain

This superfamily comprises structural domains with a topological alpha/beta knot, which is rarely found in protein structures as it poses a folding problem. Members of this superfamily includes SPOUT methyltransferases (such as tRNA:Gm18 MTase TrmH) and tRNA (guanine-N1-)-methyltransferase. The name of the SPOUT superfamily originates from its two founding members, SpoU (now known as TrmH) and TrmD. A characrteristic of this superfamily is the N-terminal Rossmanoidal alpha/beta fold fused to a C-terminal topological knot. This knot forms the binding pocket for the substrate SAM (S-adenosylmethionine), which functions as the methyl donor in the reaction. Most SPOUT methyltransferases are dimeric, with the exception of TrmD.

The TrmH structure has a disc-like shape, composed of a major catalytic domain and a helical subdomain. The catalytic domain consists of a parallel six-stranded beta-sheet, which is flanked by two alpha-helices on one side and by four alpha-helices on the other side. The N-terminal half of the catalytic domain resembles a Rossmann fold or consensus MTase fold, while the C-terminal half has a different topology as compared with that of the consensus MTase fold: it includes a deep trefoil knot. The helical subdomain consists of the N-terminal helix 1 and the C-terminal helix 8, which interact with each other.

Pfam [PfamClan:CL0098], INTERPRO:IPR029026, INTERPRO:IPR029028,PMID:24951554,PMID:15062082

GO Diversity

Unique GO annotations
79 Unique GO terms

EC Diversity

Unique EC annotations
13 Unique EC terms

Species Diversity

Unique species annotations
21384 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: 264
Domain clusters (>95% seq id): 64
Domain clusters (>35% seq id): 34
Unique PDBs: 143
Structural Clusters (5A): 5
Structural Clusters (9A): 3
FunFam Clusters: 128
Unique EC: 13
Unique GO: 79
Unique Species: 21384