SUPERFAMILY 1.75 HMM library and genome assignments server

Ribonuclease domain of colicin E3 superfamily

SCOP classification
Root:   SCOP hierarchy in SUPERFAMILY [ 0] (11)
Class:   All beta proteins [ 48724] (174)
Fold:   Ribonuclease domain of colicin E3 [ 63839]
Superfamily:   Ribonuclease domain of colicin E3 [ 63840]
Families:   Ribonuclease domain of colicin E3 [ 63841]

Superfamily statistics
Genomes (35) Uniprot 2014_06 PDB chains (SCOP 1.75)
Domains 37 338 3
Proteins 37 338 3

Functional annotation
General category Metabolism
Detailed category Nucleotide metabolism and transport

Function annotation of SCOP domain superfamilies

InterPro annotation
Cross references IPR009105 SSF63840 Protein matches

Colicins are plasmid-encoded protein antibiotics, or bacteriocins, produced by strains of Escherichia coli that kill closely related bacteria. Colicins are classified according to the cell-surface receptor they bind to, colicin E3 binding to the BtuB receptor involved in vitamin B12 uptake. The lethal action of colicin E3 arises from its ability to inactivate the ribosome by site-specific RNase cleavage of the 16S ribosomal RNA, which is carried out by the catalytic, or ribonuclease domain. Colicin E3 is comprised of three domains, each domain being involved in a different stage of infection: receptor binding, translocation and cytotoxicity. Colicin E3 is a Y-shaped molecule with the receptor-binding middle domain forming the stalk, the N-terminal translocation domain forming the two globular heads , and the C-terminal catalytic domain forming the two globular arms. To neutralise the toxic effects of colicin E3, the host cell produces an immunity protein, which binds to the C-terminal end of the ribonuclease domain and effectively suppresses its activity.

This entry represents the ribonuclease domain (also called catalytic or cytotoxic domain) found in various colicins. This domain confers cytotoxic activity to proteins, enabling the formation of nucleolytic breaks in 16S ribosomal RNA. The structure of the domain reveals a highly twisted central beta-sheet elaborated with a short N-terminal alpha-helix [PubMed10986462, PubMed11741540].

InterPro database

PDBeMotif information about ligands, sequence and structure motifs
Cross references PDB entries
Ligand binding statistics
Nucleic-acid binding statistics
Occurrence of secondary structure elements
Occurrence of small 3D structural motifs

PDBeMotif resource

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Internal database links

Browse genome assignments for this superfamily. The SUPERFAMILY hidden Markov model library has been used to carry out SCOP domain assignments to all genomes at the superfamily level.

Alignments of sequences to 1 models in this superfamily are available by clicking on the 'Alignments' icon above. PDB sequences less than 40% identical are shown by default, but any other sequence(s) may be aligned. Select PDB sequences, genome sequences, or paste in or upload your own sequences.

Browse and view proteins in genomes which have different domain combinations including a Ribonuclease domain of colicin E3 domain.

Examine the distribution of domain superfamilies, or families, across the major taxonomic kingdoms or genomes within a kingdom. This gives an immediate impression of how superfamilies, or families, are restricted to certain kingdoms of life.

Explore domain occurrence network where nodes represent genomes and edges are domain architectures (shared between genomes) containing the superfamily of interest.

There are 1 hidden Markov models representing the Ribonuclease domain of colicin E3 superfamily. Information on how the models are built, and plots showing hydrophobicity, match emmission probabilities and insertion/deletion probabilities can be inspected.

Jump to [ Top of page · SCOP classification · InterPro annotation · PDBeMotif links · Functional annotation · Internal database links ]