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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 [3]:
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.
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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). | |
PubMed ID | 2898203 |
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). | |
PubMed ID | 3118043 |
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). | |
PubMed ID | 7934814 |
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). | |
PubMed ID | 8438237 |