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323  structures 2459  species 0  interactions 12940  sequences 78  architectures

Clan: Pilus (CL0327)


Pilus subunit Add an annotation

This clan contains bacterial and archaeal systems involved in flagellar or twitching motility, adhesion, protein secretion, and DNA uptake, such as type II secretion system (T2SS), the type IV pilus or the competence pilus (Com) [4]. Pili proteins enable the transfer of plasmid between bacteria. The families in this clan adopt an alpha helical structure which is packed against a beta sheet [2-3].

This clan contains 15 families and the total number of domains in the clan is 12940. The clan was built by J Mistry.

Literature references

  1. Telford JL, Barocchi MA, Margarit I, Rappuoli R, Grandi G; , Nat Rev Microbiol. 2006;4:509-519.: Pili in gram-positive pathogens. PUBMED:16778837 EPMC:16778837
  2. Xu XF, Tan YW, Lam L, Hackett J, Zhang M, Mok YK; , J Biol Chem. 2004;279:31599-31605.: NMR structure of a type IVb pilin from Salmonella typhi and its assembly into pilus. PUBMED:15159389 EPMC:15159389
  3. Hazes B, Sastry PA, Hayakawa K, Read RJ, Irvin RT; , J Mol Biol. 2000;299:1005-1017.: Crystal structure of Pseudomonas aeruginosa PAK pilin suggests a main-chain-dominated mode of receptor binding. PUBMED:10843854 EPMC:10843854
  4. Denise R, Abby SS, Rocha EPC;, PLoS Biol. 2019;17:e3000390.: Diversification of the type IV filament superfamily into machines for adhesion, protein secretion, DNA uptake, and motility. PUBMED:31323028 EPMC:31323028


This clan contains the following 15 member families:

Arch_flagellin Bundlin ComP_DUS GspH PilA4 Pilin Pilin_GH Pilin_PilX PilJ_C PilM PilS T2SSG T2SSI T2SSJ TcpA

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
GspH (PF12019) 3169 (24.5%) View
T2SSG (PF08334) 2807 (21.7%) View
ComP_DUS (PF16732) 1758 (13.6%) View
Pilin (PF00114) 1639 (12.7%) View
T2SSI (PF02501) 1194 (9.2%) View
T2SSJ (PF11612) 956 (7.4%) View
Arch_flagellin (PF01917) 684 (5.3%) View
Pilin_GH (PF16734) 341 (2.6%) View
PilS (PF08805) 222 (1.7%) View
PilM (PF07419) 78 (0.6%) View
PilJ_C (PF18223) 32 (0.2%) View
PilA4 (PF18682) 23 (0.2%) View
Bundlin (PF05307) 18 (0.1%) View
TcpA (PF05946) 11 (0.1%) View
Pilin_PilX (PF11530) 8 (0.1%) View
Total: 15 Total: 12940 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.

Loading structure mapping...