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|Other regulatory function
Document: Function annotation of SCOP domain superfamilies
|IPR007481 SSF101738 Protein matches
Escherichia coli stringent starvation protein B (SspB), is thought to enhance the specificity of degradation of tmRNA-tagged proteins by the ClpXP protease. The tmRNA tag, also known as ssrA, is an 11-aa peptide added to the C terminus of proteins stalled during translation, targets proteins for degradation by ClpXP and ClpAP. SspB is a cytoplasmic protein that specifically binds to residues 1-4 and 7 of the tag. Binding of SspB enhances degradation of tagged proteins by ClpX, and masks sequence elements important for ClpA interactions, inhibiting degradation by ClpA . However, more recent work has cast doubt on the importance of SspB in wild-type cells . SspB is encoded in an operon whose synthesis is stimulated by carbon, amino acid, and phosphate starvation. SspB may play a special role during nutrient stress, for example by ensuring rapid degradation of the products of stalled translation, without causing a global increase in degradation of all ClpXP substrates .
PDBeMotif information about ligands, sequence and structure motifs
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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 4 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 SspB-like 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 4 hidden Markov models representing the SspB-like 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 ]