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146  structures 1613  species 0  interactions 11419  sequences 170  architectures

Clan: EsxAB (CL0352)


WXG100-A/WXG100-B dimer Add an annotation

The WXG100 protein secretion system (Wss) is responsible for the secretion of WXG100 proteins (PF06013), such as ESAT-10 (6 kDa early secreted antigenic target) and CFP-10 (10 kDa culture filtrate protein) in Mycobacterium tuberculosis or EsxA (ESAT-6-like extracellularly secreted protein A) and EsxB in Staphylococcus aureus. These two proteins, generally encoded in the same gene cluster, form a 1:1 heterodimeric complex. These proteins are virulence factors involved in host-pathogen interaction [1], as demonstrated in Mycobacterium tuberculosis, Staphylococcus aureus or Bacillus anthracis. The Wss is encoded in many other Gram-positive (monoderm) bacteria. This superfamily contains a number of DUFs which are closely related and may or may not represent the same family of proteins.

This clan contains 11 families and the total number of domains in the clan is 11419. The clan was built by RD Finn.

Literature references

  1. Burts ML, Williams WA, DeBord K, Missiakas DM; , Proc Natl Acad Sci U S A. 2005;102:1169-1174.: EsxA and EsxB are secreted by an ESAT-6-like system that is required for the pathogenesis of Staphylococcus aureus infections. PUBMED:15657139 EPMC:15657139
  2. Desvaux M, Hebraud M, Talon R, Henderson IR;, Trends Microbiol. 2009;17:338-340.: Outer membrane translocation: numerical protein secretion nomenclature in question in mycobacteria. PUBMED:19674902 EPMC:19674902
  3. Sutcliffe IC;, Antonie Van Leeuwenhoek. 2011;99:127-131.: New insights into the distribution of WXG100 protein secretion systems. PUBMED:20852931 EPMC:20852931
  4. Desvaux M, Hebraud M, Talon R, Henderson IR;, Trends Microbiol. 2009;17:139-145.: Secretion and subcellular localizations of bacterial proteins: a semantic awareness issue. PUBMED:19299134 EPMC:19299134


This clan contains the following 11 member families:

DUF2563 DUF3130 DUF4226 DUF5344 EspA_EspE EspB_PE LXG PE PPE T7SS_ESX_EspC WXG100

External database links

Domain organisation

Below is a listing of the unique domain organisations or architectures from this clan. More...

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The table below shows the number of occurrences of each domain throughout the sequence database. More...

Pfam family Num. domains Alignment
WXG100 (PF06013) 5643 (49.4%) View
PPE (PF00823) 1909 (16.7%) View
PE (PF00934) 1548 (13.6%) View
T7SS_ESX_EspC (PF10824) 1328 (11.6%) View
LXG (PF04740) 442 (3.9%) View
DUF5344 (PF17279) 168 (1.5%) View
EspA_EspE (PF18879) 144 (1.3%) View
DUF4226 (PF10774) 115 (1.0%) View
DUF2563 (PF10817) 54 (0.5%) View
EspB_PE (PF18625) 48 (0.4%) View
DUF3130 (PF11328) 20 (0.2%) View
Total: 11 Total: 11419 Clan alignment

Please note: Clan alignments can be very large and can cause problems for some browsers. Read the note above before viewing.

Family relationships

This diagram shows the relationships between members of this clan. More...

Species distribution

Tree controls


This tree shows the occurrence of the domains in this clan across different species. More...



For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the MSD group, to allow us to map Pfam domains onto UniProt three-dimensional structures. The table below shows the mapping between the Pfam families in this clan, the corresponding UniProt entries, and the region of the three-dimensional structures that are available for that sequence.

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