SUPERFAMILY 1.75 HMM library and genome assignments server


SecB-like superfamily

SCOP classification
Root:   SCOP hierarchy in SUPERFAMILY [ 0] (11)
Class:   Alpha and beta proteins (a+b) [ 53931] (376)
Fold:   SecB-like [ 54610]
Superfamily:   SecB-like [ 54611] (2)
Families:   Bacterial protein-export protein SecB [ 54612]
  SP1558-like [ 160154] (2)


Superfamily statistics
Genomes (1,295) Uniprot 2014_06 PDB chains (SCOP 1.75)
Domains 1,390 8,951 4
Proteins 1,390 8,951 4


Functional annotation
General category Processes_IC
Detailed category Transport

Document:
Function annotation of SCOP domain superfamilies

UniProtKB KeyWords (KW)

(show details)
KW termFDR (all)SDKW levelAnnotation (direct or inherited)
Biological processTransport0Least InformativeDirect
Biological processProtein transport0Moderately InformativeDirect
Biological processTranslocation0Highly InformativeDirect
Cellular componentCytoplasm0Least InformativeDirect
Post-translational modificationChaperone0InformativeDirect

Document: KW annotation of SCOP domains

InterPro annotation
Cross references IPR003708 SSF54611 Protein matches
Abstract

Secretion across the inner membrane in some Gram-negative bacteria occurs via the preprotein translocase pathway. Proteins are produced in the cytoplasm as precursors, and require a chaperone subunit to direct them to the translocase component [PubMed2202721]. From there, the mature proteins are either targeted to the outer membrane, or remain as periplasmic proteins. The translocase protein subunits are encoded on the bacterial chromosome.

The translocase itself comprises 7 proteins, including a chaperone protein (SecB), an ATPase (SecA), an integral membrane complex (SecCY, SecE and SecG), and two additional membrane proteins that promote the release of the mature peptide into the periplasm (SecD and SecF) [PubMed2202721]. The chaperone protein SecB [PubMed11336818] is a highly acidic homotetrameric protein that exists as a "dimer of dimers" in the bacterial cytoplasm. SecB maintains preproteins in an unfolded state after translation, and targets these to the peripheral membrane protein ATPase SecA for secretion [PubMed10418149].

Recently, the tertiary structure of Haemophilus influenzae SecB was resolved by means of X-ray crystallography to 2.5A [PubMed11101901]. The chaperone comprises four chains, forming a tetramer, each chain of which has a simple alpha+beta fold arrangement. While one binding site on the homotetramer recognises unfolded polypeptides by hydrophobic interactions, the second binds to SecA through the latter's C-terminal 22 residues.


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 5 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 SecB-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 5 hidden Markov models representing the SecB-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 · UniProtKB KeyWords (KW) · Internal database links ]