Genome Property Definition Page

Nameprotein sorting system, PEP-CTERM/exosortase (generic)
DescriptionThis Genome Property describes a proposed protein sorting system associated with exopolysaccharide loci in many Gram-negative bacteria. One hallmark is the presence of a paralogous domain at the C-termini of a substantial number of proteins in a single genome, usually from four to sixty-five. Features of this domain, described by TIGRFAMs model TIGR02595, are a conserved motif PEP, a transmembrane domain, and a cluster of basic residues for a total length of about 24 amino acids. We call this domain PEP-CTERM, and note that is shares a number of properties with the the LPXTG-type Gram-positive cell-wall targeting sequence. Another hallmark of this system is the presence of one or more homologs of EpsH (TIGR02602), a highly hydrophobic protein that spans the membrane eight or more times. Its surrounding genes nearly always pertain to exopolysaccharide biosynthesis. We have proposed that TIGR02602 models a transpeptidase that cleaves PEP-CTERM proteins, attaches them transiently to an active site Cys, then attaches them covalently to an unknown substrate for sorting to the outer surface of the cell, closely analogous to the action of sortase in Gram-positive bacteria. We suggest the name exosortase for EpsH homologs involved in this process. In Proteobacterial species with a the PEP-CTERM/exsortase system, a sensor histidine kinase (TIGR02916) and a sigma-54-dependent DNA-binding response regulator (TIGR02915) are present and appear to bind a conserved regulatory site found upstream of most PEP-CTERM genes.
Parent PropertyGenProp0069: cell surface component
GenProp0179: protein transport
Literature References
[ 1 ]Haft DH, Paulsen IT, Ward N, Selengut JD  Exopolysaccharide-associated protein sorting in environmental organisms: the PEP-CTERM/EpsH system. Application of a novel phylogenetic profiling heuristic.  BMC Biol. 2006 Aug 24;4(1):29.  PMID 16930487

Step NameStep NumRequiredEvidence (Method)Evidence Go Terms
PEP-CTERM motifCTERMYESTIGR02595 (HMM): PEP-CTERM protein-sorting domain
PF07589 (HMM): PEP-CTERM motif
EpsH family 8TM proteinEpsHYESTIGR02602 (HMM): exosortase
EpsI protein/fusionEpsINOTIGR02914 (HMM): EpsI family protein

Parent Properties
GenProp0069cell surface component
GenProp0179protein transport

Sibling Properties
GenProp0012outer membrane
GenProp0056type IV pilus
GenProp0158peptidoglycan(murein) biosynthesis
GenProp0297lipopolysaccharide biosynthesis
GenProp0626protein sorting system, sortase type, LPXTG/SrtA class
GenProp0664protein sorting system, sortase type, SrtB class
GenProp0725outer membrane protein assembly complex
GenProp0811S-layer homology domain-mediated cell wall binding
GenProp0857anchored repeat-class ABC transporter, P. acnes type
GenProp0859protein sorting system, proteobacterial dedicated sortase type
GenProp0052type III secretion
GenProp0053type II secretion
GenProp0054type IV secretion
GenProp0059type I secretion
GenProp0127Tat (Sec-independent) protein export
GenProp0205signal recognition system, bacterial
GenProp0207lipoprotein localization system lolABCDE
GenProp0209Sec system preprotein translocase
GenProp0295prokaryotic N-terminal cleavage/methylation, type IV pilin-like
GenProp0669protein sorting system, putative, exosortase G class
GenProp0735type VI secretion
GenProp0778protein sorting system, GlyGly-CTERM/rhombosortase
GenProp0844accessory Sec system for serine-rich glycoprotein transport
GenProp0845protein sorting system, KxYKxGKxW class
GenProp0904type VII secretion, Actinobacteria form
GenProp0905type VII secretion, Firmicutes form
GenProp0928OMP chaperone system: SurA-Skp-DegP
GenProp0957protein sorting system, SipW class
GenProp0978protein sorting system, PGF-CTERM/archaeosortase A
GenProp0979protein sorting system, PEF-CTERM/archaeosortase C
GenProp0980protein sorting system, putative, exosortase F class
GenProp0983protein sorting system, VPXXXP-CTERM/archaeosortase B
GenProp0985protein sorting system, VPDSG-CTERM/exosortase C
GenProp0986protein sorting system, VPLPA-CTERM/exosortase D
GenProp0987protein sorting system, cyano-PEP-CTERM class
GenProp0989protein sorting system, VPEID-CTERM/exosortase E
GenProp0993protein sorting system, PIP-CTERM/archaeosortase D
GenProp0996protein sorting system, IPTLxxWG-CTERM/exosortase H
GenProp0999Por secretion system
GenProp1005protein sorting system, putative, exosortase J class
GenProp1054protein sorting system, MSEP-CTERM/exosortase K
GenProp1055protein sorting system, PEFG-CTERM/thaumarchaeosortase
GenProp1074type V secretion
GenProp1087protein sorting system, vault protein/exosortase N