|PROSITE documentation PDOC00342|
A number of bacteria express filamentous adhesins known as pili. The pili are polar flexible filaments of about 5.4 nm diameter and 2500 nm average length; they consist of a single polypeptide chain (called pilin or fimbrial protein) arranged in a helical configuration of five subunits per turn in the assembled pilus. Gram-negative bacteria produce pilin which are characterized by the presence of a very short leader peptide of 6 to 7 residues, followed by a methylated N-terminal phenylalanine residue and by a highly conserved sequence of about 24 hydrophobic residues. This class of pilin is often referred to as NMePhe or type-4 pili [1,2].
Recently a number of bacterial proteins have been sequenced which share the following structural characteristics with type-4 pili :
a) The N-terminal residue, which is methylated, is hydrophobic (generally a phenylalanine or a methionine); b) The leader peptide is hydrophilic, consists of 5 to 10 residues (with two exceptions, see below) and ends with a glycine; c) The fifth residue of the mature sequence is a glutamate which seems to be required for the methylation step; d) The first twenty residues of the mature sequence are highly hydrophobic.
These proteins are listed below:
We developed a signature pattern based on the N-terminal conserved region of all these proteins.Last update:
November 1995 / Text revised.
PROSITE method (with tools and information) covered by this documentation:
|1||Authors||Paranchych W. Frost L.S.|
|Title||The physiology and biochemistry of pili.|
|Source||Adv. Microb. Physiol. 29:53-114(1988).|
|2||Authors||Dalrymple B. Mattick J.S.|
|Title||An analysis of the organization and evolution of type 4 fimbrial (MePhe) subunit proteins.|
|Source||J. Mol. Evol. 25:261-269(1987).|
|3||Authors||Hobbs M. Mattick J.S.|
|Title||Common components in the assembly of type 4 fimbriae, DNA transfer systems, filamentous phage and protein-secretion apparatus: a general system for the formation of surface-associated protein complexes.|
|Source||Mol. Microbiol. 10:233-243(1993).|
|4||Authors||Salmond G.P.C. Reeves P.J.|
|Title||Membrane traffic wardens and protein secretion in gram-negative bacteria.|
|Source||Trends Biochem. Sci. 18:7-12(1993).|