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82  structures 3793  species 12  interactions 6494  sequences 62  architectures

Clan: TypeIII_Chap (CL0097)


Type III secretory system chaperone Add an annotation

The translocation of pathogenic proteins into a host cell is mediated by the type III secretory system. A component of this system is a chaperone, which binds to the protein which is going to be secreted in the bacterial cytosol and is involved in translocation of the secreted protein, although the chaperone is not translocated itself. An individual chaperone associates with one or two specific proteins [1]. There are a large number of type III secretory system chaperones, which are small acidic proteins and exhibit significant sequence divergence. This clan groups type III secretory system chaperones. Members with a known structure form small compact globular domains with an alpha-beta(3)- alpha-beta(2)-alpha like organisation [1].

This clan contains 6 families and the total number of domains in the clan is 6494. The clan was built by RD Finn.

Literature references

  1. Birtalan S, Ghosh P; , Nat Struct Biol 2001;8:974-978.: Structure of the Yersinia type III secretory system chaperone SycE. PUBMED:11685245 EPMC:11685245


This clan contains the following 6 member families:

Autophagy_act_C CesT Chaperone_III DUF2299 Invas_SpaK YbjN

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
YbjN (PF10722) 3649 (56.2%) View
Autophagy_act_C (PF03987) 2007 (30.9%) View
CesT (PF05932) 672 (10.3%) View
DUF2299 (PF10061) 86 (1.3%) View
Invas_SpaK (PF03519) 69 (1.1%) View
Chaperone_III (PF07824) 11 (0.2%) View
Total: 6 Total: 6494 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...



There are 12 interactions for this clan. More...

Interacting families
Autophagy_act_C Autophagy_C
Autophagy_N Autophagy_act_C
CesT CesT
Chaperone_III Chaperone_III
DUF2299 DUF2299
HrpJ CesT
Invas_SpaK Invas_SpaK
ThiF Autophagy_act_C
YbjN YbjN


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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